Allow TLSv1 for compatibility with older devices

26.05 Release

See merge request simple-nixos-mailserver/nixos-mailserver!523

.git-blame-ignore-revs

@@ -0,0 +1,12 @@
+# Ignore non-functional treewide changes by configuring
+#
+#   $ git config blame.ignoreRevsFile .git-blame-ignore-revs
+#
+# or used temporarily with --ignore-revs-file=
+#
+
+# nixfmt
+1a7f3d718c5a6406b7d5b54f10f5c9c69ed90ef9
+
+# language hints
+06cc71c76eb52dc747704a317ac5e175ebdd2ba8

.gitlab-ci.yml

@@ -10,9 +10,9 @@ hydra-pr:
   variables:
     jobset: $CI_MERGE_REQUEST_IID
 
-hydra-master:
+hydra-main:
   extends: .hydra-cli
   only:
-    - master
+    - main
   variables:
-    jobset: master
+    jobset: main

.hydra/declarative-jobsets.nix

@@ -1,22 +1,21 @@
 { nixpkgs, pulls, ... }:
 
 let
-  pkgs = import nixpkgs {};
+  pkgs = import nixpkgs { };
 
   prs = builtins.fromJSON (builtins.readFile pulls);
-  prJobsets =  pkgs.lib.mapAttrs (num: info:
-    { enabled = 1;
-      hidden = false;
-      description = "PR ${num}: ${info.title}";
-      checkinterval = 300;
-      schedulingshares = 20;
-      enableemail = false;
-      emailoverride = "";
-      keepnr = 1;
-      type = 1;
-      flake = "gitlab:simple-nixos-mailserver/nixos-mailserver/merge-requests/${info.iid}/head";
-    }
-  ) prs;
+  prJobsets = pkgs.lib.mapAttrs (num: info: {
+    enabled = 1;
+    hidden = false;
+    description = "PR ${num}: ${info.title}";
+    checkinterval = 300;
+    schedulingshares = 20;
+    enableemail = false;
+    emailoverride = "";
+    keepnr = 1;
+    type = 1;
+    flake = "gitlab:simple-nixos-mailserver/nixos-mailserver/merge-requests/${info.iid}/head";
+  }) prs;
   mkFlakeJobset = branch: {
     description = "Build ${branch} branch of Simple NixOS MailServer";
     checkinterval = 300;
@@ -31,9 +30,9 @@ let
   };
 
   desc = prJobsets // {
-    "master" = mkFlakeJobset "master";
-    "nixos-24.11" = mkFlakeJobset "nixos-24.11";
-    "nixos-25.05" = mkFlakeJobset "nixos-25.05";
+    "main" = mkFlakeJobset "main";
+    "nixos-26.05" = mkFlakeJobset "nixos-26.05";
+    "nixos-25.11" = mkFlakeJobset "nixos-25.11";
   };
 
   log = {
@@ -41,13 +40,14 @@ let
     jobsets = desc;
   };
 
-in {
-  jobsets = pkgs.runCommand "spec-jobsets.json" {} ''
-    cat >$out <<EOF
+in
+{
+  jobsets = pkgs.runCommand "spec-jobsets.json" { } ''
+    cat >$out <<'EOF'
     ${builtins.toJSON desc}
     EOF
     # This is to get nice .jobsets build logs on Hydra
-    cat >tmp <<EOF
+    cat >tmp <<'EOF'
     ${builtins.toJSON log}
     EOF
     ${pkgs.jq}/bin/jq . tmp

.hydra/spec.json

@@ -12,12 +12,12 @@
   "type": 0,
   "inputs": {
     "nixexpr": {
-      "value": "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver master",
+      "value": "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver main",
       "type": "git",
       "emailresponsible": false
     },
     "nixpkgs": {
-      "value": "https://github.com/NixOS/nixpkgs 0f920b05cbcdb8c0f3c5c4a8ea29f1f0065c7033 ",
+      "value": "https://github.com/NixOS/nixpkgs nixpkgs-unstable",
       "type": "git",
       "emailresponsible": false
     },

.readthedocs.yaml

@@ -5,20 +5,22 @@
 version: 2
 
 build:
-  os: ubuntu-22.04
+  os: ubuntu-24.04
   tools:
     python: "3"
   apt_packages:
-    - nix
+    - curl
     - proot
   jobs:
     pre_install:
-      - mkdir -p ~/.nix ~/.config/nix
-      - echo "experimental-features = nix-command flakes" > ~/.config/nix/nix.conf
-      - proot -b ~/.nix:/nix /bin/sh -c "nix build -L .#optionsDoc && cp -v result docs/options.md"
+      - curl -L https://github.com/DavHau/nix-portable/releases/latest/download/nix-portable-$(uname -m) > ./nix-portable
+      - chmod +x ./nix-portable
+      - ./nix-portable nix build --print-build-logs .#optionsDoc
+      - ./nix-portable nix store cat $(readlink result) > docs/options.md
 
 sphinx:
    configuration: docs/conf.py
+   fail_on_warning: true
 
 formats:
   - pdf

.rstcheck.cfg

@@ -0,0 +1,2 @@
+[rstcheck]
+ignore_messages = Hyperlink target ".*" is not referenced.

.typos.toml

@@ -0,0 +1,2 @@
+[default.extend-identifiers]
+reportd = "reportd"

README.md

@@ -1,34 +1,32 @@
 # ![Simple Nixos MailServer][logo]
 
 ![license](https://img.shields.io/badge/license-GPL3-brightgreen.svg)
-[![pipeline status](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/badges/master/pipeline.svg)](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/commits/master)
+[![pipeline status](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/badges/main/pipeline.svg)](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/commits/main)
 
 ## Release branches
 
-For each NixOS release, we publish a branch. You then have to use the
-SNM branch corresponding to your NixOS version.
+We publish a branch for each NixOS release. Only matching branch versions are
+supported.
 
-* For NixOS 25.05
-  * Use the [SNM branch `nixos-25.05`](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/tree/nixos-25.05)
-  * [Documentation](https://nixos-mailserver.readthedocs.io/en/nixos-25.05/)
-  * [Release notes](https://nixos-mailserver.readthedocs.io/en/nixos-25.05/release-notes.html#nixos-25-05)
-* For NixOS 24.11
-  * Use the [SNM branch `nixos-24.11`](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/tree/nixos-24.11)
-  * [Documentation](https://nixos-mailserver.readthedocs.io/en/nixos-24.11/)
-  * [Release notes](https://nixos-mailserver.readthedocs.io/en/nixos-24.11/release-notes.html#nixos-24-11)
+* For NixOS 26.05
+  * Use the [`nixos-26.05`](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/tree/nixos-25.11) branch
+  * [Documentation](https://nixos-mailserver.readthedocs.io/en/nixos-26.05/)
+  * [Release notes](https://nixos-mailserver.readthedocs.io/en/nixos-26.05/release-notes.html#nixos-26-05)
 * For NixOS unstable
-  * Use the [SNM branch `master`](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/tree/master)
+  * Use the [`main`](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/tree/main) branch
   * [Documentation](https://nixos-mailserver.readthedocs.io/en/latest/)
 
 ## Features
 
-* [x] Continous Integration Testing
+* [x] Continuous Integration Testing
 * [x] Multiple Domains
 * Postfix
   * [x] SMTP on port 25
   * [x] Submission TLS on port 465
   * [x] Submission StartTLS on port 587
   * [x] LMTP with Dovecot
+  * [x] DANE and MTA-STS validation
+  * [x] SMTP TLS Reports ([RFC 8460](https://www.rfc-editor.org/rfc/rfc8460))
 * Dovecot
   * [x] Maildir folders
   * [x] IMAP with TLS on port 993
@@ -44,6 +42,8 @@ SNM branch corresponding to your NixOS version.
   * [x] Via ClamAV
 * DKIM Signing
   * [x] Via Rspamd
+  * [x] Automatic key generation
+  * [x] Multiple selectors per Domain
 * User Management
   * [x] Declarative user management
   * [x] Declarative password management
@@ -55,6 +55,8 @@ SNM branch corresponding to your NixOS version.
 * User Aliases
   * [x] Regular aliases
   * [x] Catch all aliases
+* Improve the Forwarding Experience
+  * [x] [Sender Rewriting Scheme](https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme)
 
 ### In the future
 
@@ -62,14 +64,8 @@ SNM branch corresponding to your NixOS version.
   * [ ] [Autoconfig](https://web.archive.org/web/20210624004729/https://developer.mozilla.org/en-US/docs/Mozilla/Thunderbird/Autoconfiguration)
   * [ ] [Autodiscovery](https://learn.microsoft.com/en-us/exchange/architecture/client-access/autodiscover?view=exchserver-2019)
   * [ ] [Mobileconfig](https://support.apple.com/guide/profile-manager/distribute-profiles-manually-pmdbd71ebc9/mac)
-* DKIM Signing
-  * [ ] Allow per domain selectors
-  * [ ] Allow passing DKIM signing keys
 * Improve the Forwarding Experience
   * [ ] Support [ARC](https://en.wikipedia.org/wiki/Authenticated_Received_Chain) signing with [Rspamd](https://rspamd.com/doc/modules/arc.html)
-  * [ ] Support [SRS](https://en.wikipedia.org/wiki/Sender_Rewriting_Scheme) with [postsrsd](https://github.com/roehling/postsrsd)
-* User management
-  * [ ] Allow local and LDAP user to coexist
 * OpenID Connect
   * Depends on relevant clients adding support, e.g. [Thunderbird](https://bugzilla.mozilla.org/show_bug.cgi?id=1602166)
 
@@ -90,7 +86,7 @@ See the [How to Develop SNM](https://nixos-mailserver.readthedocs.io/en/latest/h
 
 ## Contributors
 
-See the [contributor tab](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/graphs/master)
+See the [contributor tab](https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/graphs/main)
 
 ### Alternative Implementations
 

docs/Makefile

@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line, and also
 # from the environment for the first two.
-SPHINXOPTS    ?=
+SPHINXOPTS    ?= --fail-on-warning
 SPHINXBUILD   ?= sphinx-build
 SOURCEDIR     = .
 BUILDDIR      = _build

docs/add-radicale.rst

@@ -1,55 +0,0 @@
-Add Radicale
-============
-
-Configuration by @dotlambda
-
-Starting with Radicale 3 (first introduced in NixOS 20.09) the traditional
-crypt passwords are no longer supported.  Instead bcrypt passwords
-have to be used. These can still be generated using `mkpasswd -m bcrypt`.
-
-.. code:: nix
-
-   { config, pkgs, lib, ... }:
-
-   with lib;
-
-   let
-     mailAccounts = config.mailserver.loginAccounts;
-     htpasswd = pkgs.writeText "radicale.users" (concatStrings
-       (flip mapAttrsToList mailAccounts (mail: user:
-         mail + ":" + user.hashedPassword + "\n"
-       ))
-     );
-
-   in {
-     services.radicale = {
-       enable = true;
-       settings = {
-         auth = {
-           type = "htpasswd";
-           htpasswd_filename = "${htpasswd}";
-           htpasswd_encryption = "bcrypt";
-         };
-       };
-     };
-
-     services.nginx = {
-       enable = true;
-       virtualHosts = {
-         "cal.example.com" = {
-           forceSSL = true;
-           enableACME = true;
-           locations."/" = {
-             proxyPass = "http://localhost:5232/";
-             extraConfig = ''
-               proxy_set_header  X-Script-Name /;
-               proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
-               proxy_pass_header Authorization;
-             '';
-           };
-         };
-       };
-     };
-
-     networking.firewall.allowedTCPPorts = [ 80 443 ];
-   }

docs/add-roundcube.rst

@@ -1,32 +0,0 @@
-Add Roundcube, a webmail
-========================
-
-The NixOS module for roundcube nearly works out of the box with SNM. By
-default, it sets up a nginx virtual host to serve the webmail, other web
-servers may require more work.
-
-.. code:: nix
-
-   { config, pkgs, lib, ... }:
-
-   with lib;
-
-   {
-     services.roundcube = {
-        enable = true;
-        # this is the url of the vhost, not necessarily the same as the fqdn of
-        # the mailserver
-        hostName = "webmail.example.com";
-        extraConfig = ''
-          # starttls needed for authentication, so the fqdn required to match
-          # the certificate
-          $config['smtp_host'] = "tls://${config.mailserver.fqdn}";
-          $config['smtp_user'] = "%u";
-          $config['smtp_pass'] = "%p";
-        '';
-     };
-
-     services.nginx.enable = true;
-
-     networking.firewall.allowedTCPPorts = [ 80 443 ];
-   }

docs/advanced-configurations.rst

@@ -0,0 +1,23 @@
+Advanced Configurations
+=======================
+
+Congratulations on completing the `Setup Guide <setup-guide.html>`_!
+
+If you're an experienced mailserver admin, then you probably know what you want
+to do next. Our How-to guides (accessible in the navigation sidebar)
+might help you accomplish your goals. If not, consider contributing a guide!
+
+If this is your first mailserver, consider the following:
+
+- Configure regular, automatic `backups <backup-guide.html>`_.
+- Enable `fulltext search <fts.html>`_ to let clients that don’t sync all
+  mail efficiently find messages, by performing searches directly on the server.
+- Set up the `Sender Rewriting Scheme`_ if you rely on server-side mail
+  forwarding to external mail servers using mail forwards or Sieve rules.
+- Contribute `DMARC reports`_ and `SMTP TLS reports`_ to help improve email
+  security across the internet by sending feedback on authentication failures,
+  spoofing attempts, and TLS encryption issues.
+
+.. _DMARC reports: options.html#mailserver-dmarcreporting
+.. _SMTP TLS reports: options.html#mailserver-tlsrpt
+.. _Sender Rewriting Scheme: srs.html

docs/autodiscovery.rst

@@ -1,18 +1,73 @@
 Autodiscovery
 =============
 
-`RFC6186 <https://www.rfc-editor.org/rfc/rfc6186>`_ allows supporting email clients to automatically discover SMTP / IMAP addresses
-of the mailserver. For that, the following records are required:
+`RFC6186`_ defines how email clients can automatically discover a mail server's
+SMTP and IMAP endpoints. To enable this, the following DNS records must be
+configured:
 
-================= ==== ==== ======== ====== ==== =================
-Record            TTL  Type Priority Weight Port Value
-================= ==== ==== ======== ====== ==== =================
-_submission._tcp  3600 SRV  5        0      587  mail.example.com.
-_submissions._tcp 3600 SRV  5        0      465  mail.example.com.
-_imap._tcp        3600 SRV  5        0      143  mail.example.com.
-_imaps._tcp       3600 SRV  5        0      993  mail.example.com.
-================= ==== ==== ======== ====== ==== =================
+.. csv-table:: Resource record set
+   :header: "Name", "TTL", "Type", "Priority", "Weight", "Port", "Value"
+   :widths: 30, 5, 5, 5, 5, 5, 20
 
-Please note that only a few MUAs currently implement this. For vendor-specific
-discovery mechanisms `automx <https://github.com/rseichter/automx2>`_ can be used instead.
+   _submissions._tcp.example.com., 3600, SRV, 10, 1, 465, mail.example.com.
+   _imaps._tcp.example.com., 3600, SRV, 10, 1, 993, mail.example.com.
 
+
+Legacy records
+^^^^^^^^^^^^^^
+
+The following DNS records are only supported with
+:option:`mailserver.enableSubmission` and :option:`mailserver.enableImap`,
+because they only support connections with explicit TLS. These services are
+disabled by default because they are deprecated through `RFC8314 4.1`_.
+
+.. csv-table:: Resource record set
+   :header: "Name", "TTL", "Type", "Priority", "Weight", "Port", "Value"
+   :widths: 30, 5, 5, 5, 5, 5, 20
+
+   _submission._tcp.example.com., 3600, SRV, 20, 1, 587, mail.example.com.
+   _imap._tcp.example.com., 3600, SRV, 20, 1, 143, mail.example.com.
+
+Client support
+^^^^^^^^^^^^^^
+*As researched in March 2026*
+
+Only a small number of MUAs currently implement this. The most common concern
+from the bigger and security-conscious vendors is lack of widespread DNSSEC
+propagation that could be used to authenticate these SRV records.
+
+- Aerc: since 0.20.1
+
+  - ``_submissions._tcp`` support submitted in https://lists.sr.ht/~rjarry/aerc-devel/patches/68173
+
+- Evolution: Since 3.49.3 for mail accounts
+
+  - https://gitlab.gnome.org/GNOME/evolution/-/wikis/Autoconfig
+  - https://gitlab.gnome.org/GNOME/evolution/-/issues/941
+
+Unsupported
+***********
+- DeltaChat:
+
+  - https://github.com/chatmail/core/issues/1508
+
+- Thunderbird:
+
+  - Desktop: https://bugzilla.mozilla.org/show_bug.cgi?id=342242
+  - Android: https://github.com/thunderbird/thunderbird-android/issues/4721
+
+
+Vendor-specific autoconfig
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The `automx2`_ service can provide autoconfig support for Apple's
+`mobileconfig`_, Microsoft's `Autodiscover`_ and Mozilla's `Autoconfig`_
+standards. It does however lack support for multiple mail domains and isn't open for
+contributions due to copyright concerns.
+
+.. _mobileconfig: https://support.apple.com/de-de/guide/profile-manager/pmdbd71ebc9/mac
+.. _Autodiscover: https://learn.microsoft.com/en-us/exchange/architecture/client-access/autodiscover?view=exchserver-2019
+.. _Autoconfig: https://benbucksch.github.io/autoconfig-spec/draft-ietf-mailmaint-autoconfig.html
+.. _automx2: https://github.com/rseichter/automx2
+.. _RFC6186: https://www.rfc-editor.org/rfc/rfc6186
+.. _RFC8314 4.1: https://www.rfc-editor.org/rfc/rfc8314#section-4.1

docs/backup-guide.rst

@@ -5,16 +5,17 @@ First off you should have a backup of your ``configuration.nix`` file
 where you have the server config (but that is already in a git
 repository right?)
 
-Next you need to backup ``/var/vmail`` or whatever you have specified
-for the option ``mailDirectory``. This is where all the mails reside.
-Good options are a cron job with ``rsync`` or ``scp``. But really
-anything works, as it is simply a folder with plenty of files in it. If
-your backup solution does not preserve the owner of the files don’t
-forget to ``chown`` them to ``virtualMail:virtualMail`` if you copy them
-back (or whatever you specified as ``vmailUserName``, and
-``vmailGoupName``).
+Next you need to backup ``/var/vmail`` or whatever you have specified for the
+option :option:`mailserver.storage.path`. This is where all the mails reside.
+Good options are a cron job with ``rsync`` or ``scp``. But really anything
+works, as it is simply a folder with plenty of files in it. If your backup
+solution does not preserve the owner of the files don’t forget to ``chown`` them
+to ``virtualMail:virtualMail`` if you copy them back (or whatever you specified
+as :option:`mailserver.storage.owner`, and :option:`mailserver.storage.group`).
 
-Finally you can (optionally) make a backup of ``/var/dkim`` (or whatever
-you specified as ``dkimKeyDirectory``). If you should lose those don’t
-worry, new ones will be created on the fly. But you will need to repeat
-step ``B)5`` and correct all the ``dkim`` keys.
+To backup spam and ham training data, backup ``/var/lib/redis-rspamd``.
+
+Finally you can (optionally) make a backup of ``/var/dkim`` (or whatever you
+specified as :option:`mailserver.dkim.keyDirectory`). If you should lose those
+don’t worry, new ones will be created on the fly. But you will need to update
+the DKIM TXT records to reflect the new key material.

docs/conf.py

@@ -20,7 +20,7 @@
 project = "NixOS Mailserver"
 copyright = "2022, NixOS Mailserver Contributors"
 author = "NixOS Mailserver Contributors"
-
+version = "26.05"
 
 # -- General configuration ---------------------------------------------------
 

docs/dkim.rst

@@ -0,0 +1,205 @@
+.. _dkim:
+
+DKIM Signing
+============
+
+DKIM (DomainKeys Identified Mail) is an email authentication mechanism that
+allows a mailserver to digitally sign outgoing emails for a domain. Receiving
+mail servers can verify this signature using a public key published in DNS to
+confirm the message was authorized by the domain and was not modified during
+transit.
+
+How DKIM works in practice
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+1. ``bob@bar.example`` sends an email to ``alice@foo.example``. The sending
+mail server for ``bar.example`` selects one or multiple DKIM keys using a
+**selector** (e.g.,  ``mail``) and creates one or multiple cryptographic
+signature for selected headers and the message body, adding a ``DKIM-Signature``
+header that references the selector.
+
+2. The message arrives at ``foo.example``. The receiving mail server reads the
+``DKIM-Signature`` headers, looks up the public keys for ``bar.example`` for
+each of the specified selectors (e.g., ``mail._domainkey.bar.example``), and
+verifies that at least one signature matches the message content.
+
+3. With a valid signature, the receiver knows the message was authorized by
+``bar.example`` and that the signed headers and body were not modified in
+transit. If the content or signed headers were changed, the DKIM verification
+fails. The use of selectors allows ``bar.example`` to rotate or migrate keys
+without disrupting verification for previously sent messages.
+
+Enabling DKIM Signing
+~~~~~~~~~~~~~~~~~~~~~
+
+Because DKIM signing is crucial for reliable mail delivery it is enabled by
+default and without further configuration a DKIM keypair will be generated for
+each :option:`mailserver.domains` (including :option:`mailserver.srs.domain`,
+if set) based on :option:`mailserver.dkim.defaults
+<mailserver.dkim.defaults.keyLength>`.
+
+.. code:: nix
+
+  {
+    mailserver = {
+      domains = [ "example.com" ];
+      dkim.enable = true; # enabled by default
+    };
+  }
+
+
+.. note::
+  If you set up NixOS Mailserver before the `25.11 release`_ your DKIM keys were
+  generated with 1024 bit RSA and we recommend replacing them with 2048 bit
+  RSA key material per `RFC8301 3.2`_.
+
+  .. _25.11 release: release-notes.html#nixos-25-11
+  .. _RFC8301 3.2: https://www.rfc-editor.org/rfc/rfc8301#section-3.2
+
+.. _dkim-key-rotation:
+
+DKIM Key Rotation
+~~~~~~~~~~~~~~~~~
+
+DKIM key rotation replaces a domain's signing keys to maintain
+strong email authentication and support algorithm upgrades. Rotation is
+essential for migrating away from weaker or deprecated algorithms.
+
+Selectors allow multiple keys to coexist during the transition: a new key can
+be deployed under a different selector while the old key remains valid for a
+limited period to verify messages still in transit. Once all messages signed
+with the old key have been delivered, the key can be safely retired, ensuring a
+reliable migration without breaking verification.
+
+
+1. Make the automatically generated key explicit
+************************************************
+
+First we need to make sure we keep the current DKIM key configured. If you were
+relying on automatically generated keys before, you now need to start explicitly
+defining that key, because explicit selector configuration takes precedence.
+
+.. code:: nix
+
+  {
+    mailserver = {
+      domains = [ "example.com" ];
+      dkim.domains = {
+        "example.com".selectors = {
+          "${config.mailserver.dkim.defaults.selector}" = { };
+        };
+      };
+    };
+  }
+
+
+2. Create the new DKIM keypair
+******************************
+
+Next we need to create a new DKIM key with a unique selector, you can
+for example choose the current date. Without any settings passed a new
+key will be generated from the current :option:`mailserver.dkim.defaults
+<mailserver.dkim.defaults.keyLength>`, which should be sufficient.
+
+.. code:: nix
+
+  {
+    mailserver = {
+      domains = [ "example.com" ];
+      dkim = {
+        enable = true;
+        domains."example.com".selectors = {
+          "${config.mailserver.dkim.defaults.selector}" = { };
+          "rsa-2026-03" = {
+            keyType = "rsa";
+            keyLength = 2048;
+          };
+        };
+      };
+    };
+  }
+
+.. warning::
+   While DKIM does support Ed25519 keys (`RFC8463`_), many validators still lack
+   proper support and may treat Ed25519 key material as invalid. As a result,
+   mail signed only with Ed25519 DKIM keys may fail verification at some
+   receivers.
+
+   .. _RFC8463: https://datatracker.ietf.org/doc/html/rfc8463
+
+Once this configuration is applied the new keypair will be generated below
+:option:`mailserver.dkim.keyDirectory`, which defaults to ``/var/dkim``. The
+mailserver then begins signing outgoing mail with this key, so that it is now
+signing with two DKIM keys simultaneously.
+
+To allow receiving servers to verify the new DKIM signature its
+public key needs to be published into DNS. Look up the public key from
+``/var/dkim/example.com.rsa-2026-03.txt`` and create the following DNS record by
+substituting selector and public key.
+
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
+
+   rsa-2026-03._domainkey.example.com., 86400, TXT, v=DKIM1; k=rsa; p=<public key>
+
+.. note::
+  If you created an Ed25519 key, make sure to set the correct key type: ``k=ed25519``
+
+Now wait for a few minutes and then check DNS propagation to show the value specified.
+
+.. code-block:: console
+
+  $ nix-shell -p dig --command "dig @ns1.example.org TXT rsa-2026-03._domainkey.example.com"
+
+You can use https://www.mail-tester.com to test the new DKIM signature passes
+validation. They allow you to view the message source where you can check that
+the correct number of ``DKIM-Signature`` keys are present in the mail header.
+
+
+3. Stop signing with the old DKIM keypair
+*****************************************
+
+Once validation passes we need to stop signing with the old DKIM keypair, so
+mail in transit eventually stops depending on the key material we want to rotate
+out. Removing the selector will not remove the key material from disk, but it
+will stop using it to sign outgoing mail.
+
+.. code:: nix
+
+  {
+    mailserver = {
+      domains = [ "example.com" ];
+      dkim = {
+        enable = true;
+        domains."example.com".selectors = {
+          "rsa-2026-03" = {
+            keyType = "rsa";
+            keyLength = 2048;
+          };
+        };
+      }
+    }
+  }
+
+Apply the configuration.
+
+
+4. Remove the old DKIM selector from DNS
+****************************************
+
+.. warning::
+   Do not remove the DNS records for the old selector immediately. Keeping them
+   in place is essential to ensure that messages still in transit can be verified
+   and delivered successfully.
+
+Mail delivery is not always instantaneous. In the worst case, multiple retries
+over several days may be required. According to `RFC5321 4.5.4.1`_ delivery
+should be retried for at least 4-5 days.
+
+This means messages signed only with the old DKIM key could still be in transit
+and rely on the old selector to verify their signatures. To ensure reliable
+delivery, we recommend waiting **at least five days** before removing the old
+DKIM selector from DNS.
+
+.. _RFC5321 4.5.4.1: https://www.rfc-editor.org/rfc/rfc5321#section-4.5.4.1

docs/faq.rst

@@ -13,7 +13,7 @@ domain ``example.com`` and send mails with any address of this domain:
 
 .. code:: nix
 
-    mailserver.loginAccounts = {
+    mailserver.accounts = {
         "user@example.com" = {
             aliases = [ "@example.com" ];
         };

docs/flakes.nix

@@ -0,0 +1,35 @@
+{
+  description = "NixOS configuration";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05-small";
+
+    simple-nixos-mailserver.url = "gitlab:simple-nixos-mailserver/nixos-mailserver/nixos-26.05";
+    simple-nixos-mailserver.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs =
+    {
+      nixpkgs,
+      simple-nixos-mailserver,
+      ...
+    }:
+    {
+      nixosConfigurations = {
+        hostname = nixpkgs.lib.nixosSystem {
+          system = "x86_64-linux"; # or aarch64-linux
+          modules = [
+            simple-nixos-mailserver.nixosModule
+            {
+              mailserver = {
+                enable = true;
+
+                # Check the setup guide if you have no idea how to continue
+                # from here!
+              };
+            }
+          ];
+        };
+      };
+    };
+}

docs/flakes.rst

@@ -1,30 +1,18 @@
-Nix Flakes
-==========
+Flakes
+======
 
-If you're using `flakes <https://wiki.nixos.org/wiki/Flakes>`__, you can use
-the following minimal ``flake.nix`` as an example:
+To use NixOS mailserver `Nix flakes`_, the following minimal ``flake.nix`` can
+serve as an example to get started:
 
-.. code:: nix
+.. _Nix flakes: https://wiki.nixos.org/wiki/Flakes
 
-   {
-     description = "NixOS configuration";
+.. literalinclude:: ./flakes.nix
+   :language: nix
 
-     inputs.simple-nixos-mailserver.url = "gitlab:simple-nixos-mailserver/nixos-mailserver/nixos-20.09";
 
-     outputs = { self, nixpkgs, simple-nixos-mailserver }: {
-       nixosConfigurations = {
-         hostname = nixpkgs.lib.nixosSystem {
-           system = "x86_64-linux";
-           modules = [
-             simple-nixos-mailserver.nixosModule
-             {
-               mailserver = {
-                 enable = true;
-                 # ...
-               };
-             }
-           ];
-         };
-       };
-     };
-   }
+Lock the inputs and deploy the system closure:
+
+.. code-block:: console
+
+   nix flake lock
+   nixos-rebuild --target-host root@mail.example.com --flake .#hostname switch

docs/fts.rst

@@ -4,7 +4,7 @@ Full text search
 By default, when your IMAP client searches for an email containing some
 text in its *body*, dovecot will read all your email sequentially. This
 is very slow and IO intensive. To speed body searches up, it is possible to
-*index* emails with a plugin to dovecot, ``fts_flatcurve``.
+*index* emails with the ``fts_flatcurve`` dovecot plugin.
 
 Enabling full text search
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -20,48 +20,50 @@ To enable indexing for full text search here is an example configuration.
         enable = true;
         # index new email as they arrive
         autoIndex = true;
-        enforced = "body";
+        # only query index
+        fallback = false;
       };
     };
   }
 
 
-The ``enforced`` parameter tells dovecot to fail any body search query that cannot
-use an index. This prevents dovecot to fall back to the IO-intensive brute
-force search.
+Disabling the :option:`mailserver.fullTextSearch.fallback` option tells dovecot
+to fail any body search query that cannot use an index. This prevents Dovecot to
+fall back to the IO-intensive brute force search.
 
-If you set ``autoIndex`` to ``false``, indices will be created when the IMAP client
-issues a search query, so latency will be high.
+If you set :option:`mailserver.fullTextSearch.autoIndex` to ``false``, indices
+will be created when the IMAP client issues a search query, so latency will
+be high.
 
 Resource requirements
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
-Indices created by the full text search feature can take more disk
-space than the emails themselves. By default, they are kept in the
-emails location. When enabling the full text search feature, it is
-recommended to move indices in a different location, such as
-(``/var/lib/dovecot/indices``) by using the option
-``mailserver.indexDir``.
+Indices created by the full text search feature can take more disk space than
+the emails themselves. By default, they are kept within the maildir. When
+enabling the full text search feature, it is recommended to move indices in a
+different location, such as (``/var/lib/dovecot/indices``) by configuring
+:option:`mailserver.indexDir`.
 
 .. warning::
 
-   When the value of the ``indexDir`` option is changed, all dovecot
-   indices needs to be recreated: clients would need to resynchronize.
+   When the value of the :option:`mailserver.indexDir` option is changed, all
+   dovecot indices needs to be recreated: clients would need to resynchronize.
 
-Indexation itself is rather resouces intensive, in CPU, and for emails with
+Indexation itself is rather resource intensive, in CPU, and for emails with
 large headers, in memory as well. Initial indexation of existing emails can take
-hours. If the indexer worker is killed or segfaults during indexation, it can
-be that it tried to allocate more memory than allowed. You can increase the memory
-limit by eg ``mailserver.fullTextSearch.memoryLimit = 2000`` (in MiB).
+hours. If the indexer worker is killed or segfaults during indexation, it can be
+that it tried to allocate more memory than allowed. You can increase the default
+memory limit through :option:`mailserver.fullTextSearch.memoryLimit`.
 
 Mitigating resources requirements
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 You can:
 
-* exclude some headers from indexation with ``mailserver.fullTextSearch.headerExcludes``
-* disable expensive token normalisation in ``mailserver.fullTextSearch.filters``
-* disable automatic indexation for some folders with
-  ``mailserver.fullTextSearch.autoIndexExclude``.  Folders can be specified by
-  name (``"Trash"``), by special use (``"\\Junk"``) or with a wildcard.
+* exclude some headers from indexation with :option:`mailserver.fullTextSearch.headerExcludes`
+* disable expensive token normalisation in :option:`mailserver.fullTextSearch.filters`
+* disable automatic indexation for individual mailboxes by overriding
+  `fts_autoindex`_ on the mailbox level. This is exposed via
+  :option:`mailserver.mailboxes`, where all default mailboxes are defined.
 
+.. _fts_autoindex: https://doc.dovecot.org/main/core/plugins/fts.html#fts_autoindex

docs/howto-develop.rst

@@ -38,8 +38,8 @@ You can then run the testsuite via
 
    $ nix flake check -L
 
-Since Nix doesn't garantee your machine have enough resources to run
-all test VMs in parallel, some tests can fail. You would then haev to
+Since Nix doesn't guarantee your machine have enough resources to run
+all test VMs in parallel, some tests can fail. You would then have to
 run tests manually. For instance:
 
 ::
@@ -64,3 +64,44 @@ To build the documentation, you need to enable `Nix Flakes
 
    $ nix build .#documentation
    $ xdg-open result/index.html
+
+
+Manual migrations
+-----------------
+
+We need to take great care around providing a migration story around breaking
+changes. If manual intervention becomes necessary we provide the `stateVersion`
+option to notify the user that they need to complete a migration before
+they can deploy an update.
+
+If that is the case for your change, find the highest `stateVersion` that is
+being asserted on in `mail-server/assertions.nix`. Then pick the next number
+and add a new assertion, write a good summary describing the issue and what
+remediation steps are necessary. Finally reference the URL to the specific
+section on the migration page in the documentation.
+
+.. code-block:: nix
+
+  {
+    assertions = [
+      {
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 1;
+        message = ''
+          Problem: The home directory for the foobar service is snafu.
+          Remediation:
+            - Stop the `foobar.service`
+            - Rename `/var/lib/foobaz` to `/var/lib/foobar`
+            - Increase the `mailserver.stateVersion` to 1.
+
+          Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#specific-anchor-here for further details.
+        '';
+      }
+    ];
+  }
+
+The setup guide should always reference the latest `stateVersion`, since we
+don't require any migration steps for new setups.
+
+The migration documentation should paint a more complete picture about the steps
+that need to be carried out and why this has become necessary. Make sure to
+reference the correct anchor in the URL you put into the assertion message.

docs/index.rst

@@ -14,23 +14,42 @@ Welcome to NixOS Mailserver's documentation!
    :maxdepth: 2
 
    setup-guide
+   advanced-configurations
    howto-develop
    faq
    release-notes
    options
+   migrations
 
 .. toctree::
    :maxdepth: 1
+   :caption: Account backends
+
+   ldap
+
+.. toctree::
+   :maxdepth: 1
+   :caption: Features
+
+   dkim
+   fts
+   srs
+
+.. toctree::
+   :maxdepth: 0
    :caption: How-to
 
-   backup-guide
-   add-radicale
-   add-roundcube
-   rspamd-tuning
-   fts
-   flakes
    autodiscovery
-   ldap
+   backup-guide
+   flakes
+   rspamd-tuning
+
+.. toctree::
+   :maxdepth: 0
+   :caption: Integrations
+
+   radicale
+   roundcube
 
 Indices and tables
 ==================

docs/ldap-attrs.nix

@@ -0,0 +1,12 @@
+{
+  mailserver = {
+    ldap = {
+      attributes = {
+        uuid = "entryUUID";
+        username = "uid";
+        password = "userPassword";
+        mail = "mail";
+      };
+    };
+  };
+}

docs/ldap-basic.nix

@@ -0,0 +1,17 @@
+{
+  mailserver = {
+    ldap = {
+      enable = true;
+      uris = [
+        "ldaps://ldap1.example.com"
+        "ldaps://ldap2.example.com"
+      ];
+      bind = {
+        dn = "cn=mail,dc=example=dc=com";
+        passwordFile = "/run/keys/ldap-bind-pw";
+      };
+      base = "ou=users,dc=example,dc=com";
+      scope = "one";
+    };
+  };
+}

docs/ldap.rst

@@ -1,14 +1,96 @@
-LDAP Support
-============
+.. _ldap-top:
 
-It is possible to manage mail user accounts with LDAP rather than with
-the option `loginAccounts <options.html#mailserver-loginaccounts>`_.
+LDAP
+====
 
-All related LDAP options are described in the `LDAP options section
-<options.html#mailserver-ldap>`_ and the `LDAP test
-<https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/blob/master/tests/ldap.nix>`_
-provides a getting started example.
+LDAP (Lightweight Directory Access Protocol) is a protocol for accessing and
+managing a centralized directory of user and group information. It can be used
+to authenticate users and provide a single source of truth for email accounts
+and aliases across mail services.
 
-.. note::
-   The LDAP support can not be enabled if some accounts are also defined with ``mailserver.loginAccounts``.
 
+Requirements
+~~~~~~~~~~~~
+
+To enable the LDAP integration the following requirements must be fulfilled:
+
+- Existing LDAP service (we currently only test against OpenLDAP)
+- Bind credentials against LDAP with permissions to
+
+  - search for the acceptable set of users
+  - read the :option:`mailserver.ldap.attributes.password` attribute
+
+- Each user entry must provide attributes that can serve as
+
+  - :option:`mailserver.ldap.attributes.mail` (primary mail address)
+  - :option:`mailserver.ldap.attributes.username` (login name)
+  - :option:`mailserver.ldap.attributes.password` (login password)
+  - :option:`mailserver.ldap.attributes.uuid` (stable identifier)
+
+
+Features
+~~~~~~~~
+
+We currently have a basic feature set covering user accounts only and try to
+follow best practices to simplify maintenance.
+
+- Users authenticate with the username and password attribute
+- Maildir storage paths are constructed using the uuid attribute
+- Primary mail address read from mail attribute
+
+
+Limitations
+~~~~~~~~~~~
+
+Design choices
+^^^^^^^^^^^^^^
+
+These are intentional choices in how the mail server operates that affect the
+LDAP integration.
+
+- For mail address routing local accounts always take priority over LDAP accounts.
+
+Planned
+^^^^^^^
+
+These are features we are interested in but require implementation,
+documentation and tests.
+
+- Aliases based on LDAP attributes
+- Quotas based on LDAP attributes
+
+Avoided
+^^^^^^^
+
+The following features will likely never be implemented, since they would
+complicate the setup significantly.
+
+- Domains based on LDAP entries (would require integration with everything we
+  already do for :option:`mailserver.domains`)
+- Use of ``homeDirectory``, ``uid``, ``gid`` LDAP attributes (we are
+  committed to a virtual setup with one vmail user/uid/gid and UUID based home
+  directories)
+- Declarative aliases through :option:`mailserver.aliases`. These are limited
+  to local accounts, because Postfix enforces sender ownership based on login
+  identity and does not consult virtual aliases for authorization.
+
+Enabling LDAP support
+~~~~~~~~~~~~~~~~~~~~~
+
+Enable the LDAP integration by configuring an authenticated LDAP connection
+and how to locate all users. The bind DN must be allowed to read the configured
+password attribute, which may require additional configuration
+
+.. literalinclude:: ./ldap-basic.nix
+   :language: nix
+
+We provide sensible defaults for each attribute, that can be adapted to your
+local setup.
+
+.. literalinclude:: ./ldap-attrs.nix
+   :language: nix
+
+Refer to our `LDAP test`_ for an complete example, and see the `LDAP options`_ section for all possible settings.
+
+.. _LDAP options: options.html#mailserver-ldap
+.. _LDAP test: https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/blob/main/tests/ldap.nix

docs/migrations.rst

@@ -0,0 +1,299 @@
+Migrations
+==========
+
+With mail server configuration best practices changing over time we might need
+to make changes that require you to complete manual migration steps before you
+can deploy a new version of NixOS mailserver.
+
+The initial :option:`mailserver.stateVersion` value should be copied from the
+setup guide that you used to initially set up your mail server. If in doubt you
+can always initialize it at ``1`` and walk through all assertions, that might
+apply to your setup.
+
+NixOS 26.05
+-----------
+
+.. _migration-5:
+
+#5 Sieve script directory migration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Sieve scripts managed by users via ManageSieve were previously stored in
+``/var/sieve`` (or via the now-removed option
+``mailserver.sieveDirectory``). This setup partially mirrored the mail
+directory structure in ``/var/vmail`` (``mailserver.storage.path``),
+which proved to be fragile and error-prone.
+
+Thanks to a `prior migration`_, we can now migrate these directories into each
+user’s home directory, aligning with upstream recommendations — almost
+nine years later.
+
+.. _prior migration: #dovecot-mail-directory-migration
+
+This migration is only required if you have :option:`mailserver.enableManageSieve` enabled.
+
+1. If you are coming from ``25.11`` and are using LDAP, temporarily disable
+   :option:`mailserver.enableManageSieve` by setting it to ``false``, deploy,
+   and only then continue with this migration.
+
+   If you are not coming from ``25.11`` or are not using LDAP, continue with
+   this migration as is.
+
+2. Copy the migration script to your mailserver and make it executable:
+
+   .. code-block:: console
+
+      cd /tmp
+      wcurl https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/raw/main/migrations/nixos-mailserver-migration-05.py
+      chmod +x nixos-mailserver-migration-05.py
+
+3. Stop the ``postfix.service``.
+
+   .. code-block:: bash
+
+      systemctl stop postfix.service
+
+4. Create a backup or snapshot of your ``mailserver.sieveDirectory``, so
+   you can restore should anything go wrong.
+
+5. Run the migration script and pass your ``mailserver.sieveDirectory`` as argument:
+
+   The script should be run under the user who owns the ``mailserver.sieveDirectory``.
+   If run as root it will automatically switch into the appropriate user by itself.
+
+   The script will not modify your data unless called with ``--execute``.
+
+   The migration script finds all Sieve script directories in
+   ``/var/sieve/`` (or any other ``mailserver.sieveDirectory``), for
+   example that of ``bob`` at ``/var/vmail/bob@example.com``.
+
+   It then takes ``bob@example.com`` and looks up the home directory
+   for ``bob``. Finally, it starts suggesting the necessary move
+   operations to migrate the Sieve directory to
+   ``/var/vmail/example.com/bob/sieve`` and symlinks the active script
+   to ``/var/vmail/example.com/bob/.dovecot.sieve``.
+
+   Example:
+
+   .. code-block:: bash
+
+      ./nixos-mailserver-migration-05.py \
+         /var/sieve
+
+6. Review the script output.
+
+   The script can highlight various inconsistencies and problems, that should
+   be reviewed and acted upon.
+
+   If in doubt, join our community chat for help before applying any changes.
+
+7. Rerun the command with ``--execute`` or run the proposed commands manually.
+
+8. Update the ``mailserver.stateVersion`` to ``5``.
+
+9. The previous Sieve directory (``mailserver.sieveDirectory``) should now be safe to delete.
+
+10. If you temporarily disabled :option:`mailserver.enableManageSieve` in step 1,
+    re-enable it now by setting it back to ``true``.
+
+.. _migration-4:
+
+#4 Dovecot LDAP UUID-based home directories
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+LDAP Support in NixOS mailserver was introduced during the 23.11 release cycle
+and came with a number of flaws that we are correcting now, three years later.
+
+This particular migration is needed because up until now we were
+relying on email addresses to construct the Dovecot home directory path
+(``var/vmail/ldap/user@example.com``) which is fragile: addresses can
+change, requiring manual homedir relocation. Switching to UUID-based homedirs
+(``/var/vmail/ldap/<uuid>``) ensures stable, unique paths and applies well-known
+best practices to mailserver management.
+
+1. Copy the migration script to your mailserver and make it executable:
+
+   .. code-block:: console
+
+      cd /tmp
+      wcurl https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/raw/main/migrations/nixos-mailserver-migration-04.py
+      chmod +x nixos-mailserver-migration-04.py
+
+2. Stop the ``dovecot.service``.
+
+   .. code-block:: bash
+
+      systemctl stop dovecot.service
+
+3. Create a backup or snapshot of your :option:`mailserver.storage.path`, so
+   you can restore should anything go wrong.
+
+4. Run the migration script and pass the required arguments to enable LDAP lookups:
+
+   The script should be run under the user who owns the :option:`mailserver.storage.path`.
+   If run as root it will automatically switch into the appropriate user by itself.
+
+   The script will not modify your data unless called with ``--execute``.
+
+   The migration script finds all Dovecot home directories in
+   ``/var/vmail/ldap/`` (or any other :option:`mailserver.storage.path`),
+   for example that of bob at ``/var/vmail/ldap/bob@example.com``.
+   It then takes ``bob@example.com`` and queries the LDAP server for
+   ``mail=bob@example.com`` to retrieve the UUID attribute. Finally
+   it starts suggesting the necessary move operations to arrive at
+   ``/var/vmail/ldap/f3b4e8ea-087f-42cc-95f0-cbfd99386092`` for bob.
+
+   Example:
+
+   .. code-block:: bash
+
+      ./nixos-mailserver-migration-04.py \
+        --ldap-uri ldaps://ldap1.example.com
+        --ldap-bind-dn cn=mail,ou=accounts,dc=example,dc=com \
+        --ldap-bind-pw-file /run/keys/ldap-bind-pw \
+        --ldap-base ou=people,ou=accounts,dc=example,dc=com \
+        --ldap-scope sub \
+        --ldap-filter "(mail=%s)" \
+        --ldap-attr-uuid entryUUID \
+         /var/vmail
+
+   For the ``--ldap-attr-uuid`` parameter we expect a long-term stable
+   identifier, ideally a UUID field. The exact attribute name depends on your
+   LDAP implementation, for example:
+
+   - Authentik: ``uid`` `[1]`_
+   - Kanidm: ``uuid`` `[2]`_
+   - Keycloak ``entryUUID``
+   - OpenLDAP: ``entryUUID`` (`RFC4530`_)
+
+   If your LDAP provider isn't listed you can determine the correct
+   attribute by querying a user entry with ``ldapsearch``. Finally, configure
+   :option:`mailserver.ldap.attributes.uuid` accordingly.
+
+   Add ``--ldap-starttls`` if you use the the `ldap://` URI scheme and require
+   explicit TLS.
+
+   .. _[1]: https://docs.goauthentik.io/add-secure-apps/providers/ldap#users
+   .. _[2]: https://kanidm.github.io/kanidm/stable/integrations/ldap.html#data-mapping
+   .. _RFC4530: https://www.rfc-editor.org/rfc/rfc4530.html
+
+5. Review the script output.
+
+   It's primary job is to determine the UUID for an LDAP account, so that it
+   can rename the Dovecot home directory from mail address to UUID within the
+   same directory.
+
+   The script can highlight various inconsistencies and problems, that should
+   be reviewed and acted upon.
+
+   If in doubt, join our community chat for help before applying any changes.
+
+6. Rerun the command with ``--execute`` or run the proposed commands manually.
+
+7. Update the ``mailserver.stateVersion`` to ``4``.
+
+NixOS 25.11
+-----------
+
+#3 Dovecot mail directory migration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The way the Dovecot home directory for login accounts were previously set up
+resulted in shared home directories for all those users. This is not a
+supported Dovecot configuration.
+
+To resolve this we migrated the home directory into the individual
+`domain/localpart` subdirectory below the `mailserver.mailDirectory`.
+
+But since this now overlaps with the location of the Maildir, it must be
+migrated into the `mail/` directory below the home directory.
+And while the LDAP home directory is not affected we use this migration to
+keep the Maildir configurations of LDAP users in sync with those of local
+accounts.
+
+This is a big step forward, since we can now more cleanly colocate other
+data directories, like sieve in the home directory, which in turn simplifies
+backups.
+
+This migration is required for every configuration.
+
+For remediating this issue the following steps are required:
+
+1. Copy the `migration script <https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/blob/main/migrations/nixos-mailserver-migration-03.py>`_ script to your mailserver
+   and make it executable:
+
+   .. code-block:: bash
+
+      wcurl https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/raw/main/migrations/nixos-mailserver-migration-03.py
+      chmod +x nixos-mailserver-migration-03.py
+
+2. Stop the ``dovecot.service``.
+
+   .. code-block:: bash
+
+      systemctl stop dovecot.service
+
+3. Create a backup or snapshot of your ``mailserver.mailDirectory``, so you can restore
+   should anything go wrong.
+
+4. Run the migration script under your virtual mail user with the following arguments:
+
+   - ``--layout default`` unless ``useFSLayout`` is enabled, then ``--layout folder``
+   - The value of ``mailserver.mailDirectory``, which defaults to ``/var/vmail``
+
+   The script should be run under the user who owns the ``mailDirectory``.
+   If run as root it will try to switch into the appropriate user by itself.
+
+   The script will not modify your data unless called with ``--execute``.
+
+   Example:
+
+   .. code-block:: bash
+
+      ./nixos-mailserver-migration-03.py --layout default /var/vmail
+
+5. Review the commands. They should be
+
+   - create a ``mail`` directory for each account,
+   - move maildir contents from the parent directory into it,
+   - suggest removal of files that do not belong to the maildir
+
+      - their removal is not mandatory and the script **will not** remove them when called with ``--execute``
+      - review these items carefully if you want to remove them yourself
+
+   - remove obsolete files from the old home directory location
+
+6. Rerun the command with ``--execute`` or run the commands manually.
+
+7. Update the ``mailserver.stateVersion`` to ``3``.
+
+#2 Dovecot LDAP home directory migration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The Dovecot configuration for LDAP home directories previously did not respect
+the ``mailserver.mailDirectory`` setting.
+
+This means that home directories were unconditionally located at
+``/var/vmail/ldap/%{user}``.
+
+This migration is required if you both:
+
+* enabled the LDAP integration (``mailserver.ldap.enable``)
+* and customized the default mail directory (``mailserver.mailDirectory != "/var/vmail"``)
+
+For remediating this issue the following steps are required:
+
+1. Stop ``dovecot.service``.
+2. Move ``/var/vmail/ldap`` below your ``mailserver.mailDirectory``.
+3. Update the ``mailserver.stateVersion`` to ``2``.
+
+#1 Initialization
+^^^^^^^^^^^^^^^^^
+
+This option was introduced in the NixOS 25.11 release cycle, in which case you
+can safely initialize its value at `1`.
+
+.. code-block:: nix
+
+   mailserver.stateVersion = 1;
+

docs/radicale.nix

@@ -0,0 +1,55 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+
+let
+  inherit (lib)
+    concatStrings
+    flip
+    mapAttrsToList
+    ;
+
+  mailAccounts = config.mailserver.accounts;
+  htpasswd = pkgs.writeText "radicale.users" (
+    concatStrings (flip mapAttrsToList mailAccounts (mail: user: "${mail}+:${user.hashedPassword}\n"))
+  );
+
+in
+{
+  services.radicale = {
+    enable = true;
+    settings = {
+      auth = {
+        type = "htpasswd";
+        htpasswd_filename = "${htpasswd}";
+        htpasswd_encryption = "bcrypt";
+      };
+    };
+  };
+
+  services.nginx = {
+    enable = true;
+    virtualHosts = {
+      "cal.example.com" = {
+        forceSSL = true;
+        enableACME = true;
+        locations."/" = {
+          proxyPass = "http://localhost:5232/";
+          extraConfig = ''
+            proxy_set_header  X-Script-Name /;
+            proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_pass_header Authorization;
+          '';
+        };
+      };
+    };
+  };
+
+  networking.firewall.allowedTCPPorts = [
+    80
+    443
+  ];
+}

docs/radicale.rst

@@ -0,0 +1,29 @@
+Radicale
+========
+
+Radicale is a lightweight open-source CalDAV/CardDAV server that stores
+calendars and contacts as plain files on the filesystem, enabling simple
+self-hosted synchronization with standard clients.
+
+Limitations
+^^^^^^^^^^^
+
+Radicale since the 3.x release (introduced in NixOS 20.09) does not support
+traditional crypt() password hashes any longer. To establish access for
+existing :option:`mailserver.accounts`, the hashing method used
+for ``hashedPassword`` needs to be compatible with one of the available
+`htpasswd_encryption`_ methods. Such hashes can for example be created using
+
+.. code-block:: console
+
+   nix-shell -p mkpasswd --command "mkpasswd -m bcrypt"
+
+.. _htpasswd_encryption: https://radicale.org/v3.html#htpasswd_encryption
+
+Code
+^^^^
+
+Configuration contributed by Robert Schütz (@dotlambda).
+
+.. literalinclude:: ./radicale.nix
+   :language: nix

docs/release-notes.rst

@@ -1,6 +1,135 @@
 Release Notes
 =============
 
+NixOS 26.05
+-----------
+
+Features
+^^^^^^^^
+
+- :ref:`DKIM key management <dkim>` now supports multiple selectors per domain,
+  enabling :ref:`key rotation <dkim-key-rotation>`. Pre-created key material is
+  also supported. Existing automatically generated DKIM keys from before 25.11
+  use 1024-bit RSA and should be rotated. See :option:`mailserver.dkim.domains`.
+
+- Certificate handling was simplified. We recommend using the NixOS
+  ACME module (``security.acme.certs``) and referencing a certificate
+  configuration by name. Alternatively, certificate and private key can be
+  managed manually. Configure either :option:`mailserver.x509.useACMEHost`
+  or :option:`mailserver.x509.certificateFile` and
+  :option:`mailserver.x509.privateKeyFile`. See the updated :ref:`setup guide
+  <setup-guide>` for a basic ACME HTTP-01 example.
+
+- Local mail accounts can now use managed cleartext passwords. This integrates
+  well with secret management tools such as `agenix`_ and `sops-nix`_ while
+  avoiding password leakage into the world-readable Nix store. See
+  :option:`mailserver.accounts.<name>.passwordFile`.
+
+- Blocked sender responses can now be customized. This is useful if you require GDPR
+  compliance. See :option:`mailserver.rejectSenderMessage`.
+
+Security
+^^^^^^^^
+
+- TLSv1.2 cipher suites in Postfix now require `AEAD`_ and `ECDHE`_.
+
+- Postfix and Dovecot now support negotiation of the ``SecP256r1MLKEM768``
+  key agreement mechanism. The `standardization process
+  <https://datatracker.ietf.org/doc/draft-ietf-tls-ecdhe-mlkem/>`__ is ongoing.
+
+- Deprecated and obsolete TLS signature algorithms were removed from Postfix.
+
+Sieve
+^^^^^
+
+- **Migration**: When ManageSieve is enabled, user-created Sieve scripts must
+  be migrated into their Dovecot home directory. See the :ref:`migration guide
+  <migration-5>`.
+
+LDAP
+^^^^
+
+- **Migration**: Dovecot home directories for LDAP users must be migrated to
+  UUID-based directory names. The UUID attribute can be customized through
+  :option:`mailserver.ldap.attributes.uuid`. See the :ref:`migration guide
+  <migration-4>`.
+
+- The LDAP configuration has been revamped. Option names have been simplified,
+  examples and documentation improved. The :ref:`LDAP documentation <ldap-top>`
+  was written from the ground up.
+
+- The default LDAP login attribute changed from ``mail`` to ``uid``.
+  This allows users to login with their account name rather than
+  their email address, which is more convenient and consistent with
+  typical LDAP practices. The exact attribute can be customized through
+  :option:`mailserver.ldap.attributes.username`.
+
+- The LDAP bind password is now read verbatim without trimming whitespace. Any
+  trailing newline is now preserved and may cause authentication failures.
+
+- Local and LDAP accounts can now coexist. For overlapping accounts and addresses
+  the local account will always win.
+
+
+Internals
+^^^^^^^^^
+
+- Dovecot has been updated from 2.3 to 2.4 and now relies on the structured settings option.
+
+Deprecations
+^^^^^^^^^^^^
+
+The following integrations are deprecated and will be removed before the next
+release:
+
+- :option:`mailserver.borgbackup.enable`
+- :option:`mailserver.backup.enable`
+- :option:`mailserver.monitoring.enable`
+
+.. _key rotation: dkim.html#dkim-key-rotation
+.. _agenix: https://github.com/ryantm/agenix
+.. _sops-nix: https://github.com/Mic92/sops-nix
+.. _AEAD: https://en.wikipedia.org/wiki/Authenticated_encryption
+.. _ECDHE: https://www.rfc-editor.org/rfc/rfc8422
+
+NixOS 25.11
+-----------
+
+- The ``systemName`` and ``systemDomain`` options have been introduced to have
+  reusable configurations for automated reports (DMARC, TLSRPT). They come with
+  reasonable defaults, but it is suggested to check and change them as needed.
+- Support for the `Sender Rewriting Scheme`_ has been added, which allows
+  forwarding mail without breaking SPF by rewriting the envelope address.
+- The default key length for new DKIM RSA keys was increased to 2048 bits as
+  recommended in `RFC 8301 3.2`_.
+  We recommend rotating existing keys, as the RFC advises that signatures from
+  1024 bit keys should not be considered valid any longer.
+- IMAP access over port ``143/tcp`` is now default disabled in line
+  with `RFC 8314 4.1`_. Use IMAP over implicit TLS on port ``993/tcp``
+  instead. If you still require this feature you can re-enable it using
+  ``mailserver.enableImap``, but it is scheduled for removal after the 25.11
+  release.
+- SMTP server and client now support and prefer a hybrid key exchange
+  (X25519MLKEM768)
+- SMTP access over STARTTLS on port ``587/tcp`` is now default disabled in line
+  with `RFC 8314 3.3`_. If you still require this feature you can re-enable it
+  using ``mailserver.enableSubmission``.
+- DMARC reports are now sent with the ``noreply-dmarc`` localpart from the
+  system domain.
+- DANE and MTA-STS are now validated for outgoing SMTP connections using
+  `postfix-tlspol`_.
+- SMTP TLS connection reports (`RFC 8460`_) are now supported using
+  `tlsrpt-reporter`_. They can be enabled with the ``mailserver.tlsrpt.enable``
+  option.
+
+.. _Sender Rewriting Scheme: srs.html
+.. _RFC 8301 3.2: https://www.rfc-editor.org/rfc/rfc8301#section-3.2
+.. _RFC 8314 3.3: https://www.rfc-editor.org/rfc/rfc8314#section-3.3
+.. _RFC 8314 4.1: https://www.rfc-editor.org/rfc/rfc8314#section-4.1
+.. _RFC 8460: https://www.rfc-editor.org/rfc/rfc8460
+.. _postfix-tlspol: https://github.com/Zuplu/postfix-tlspol
+.. _tlsrpt-reporter: https://github.com/sys4/tlsrpt-reporter
+
 NixOS 25.05
 -----------
 

docs/roundcube-caddy.nix

@@ -0,0 +1,17 @@
+{ config, ... }:
+{
+  services.nginx.virtualHosts.${config.services.roundcube.hostName} = {
+    forceSSL = false;
+    enableACME = false;
+    listen = [
+      {
+        addr = "127.0.0.1";
+        port = 8000;
+      }
+    ];
+  };
+
+  services.caddy.virtualHosts."${config.services.roundcube.hostName}".extraConfig = ''
+    reverse_proxy localhost:8000
+  '';
+}

docs/roundcube.nix

@@ -0,0 +1,49 @@
+{
+  config,
+  pkgs,
+  ...
+}:
+
+{
+  services.roundcube = {
+    enable = true;
+    hostName = "webmail.example.com"; # the nginx vhost
+    package = pkgs.roundcube.withPlugins (
+      plugins: with plugins; [
+        # external plugins to be included
+        # https://search.nixos.org/packages?query=roundcubePlugins
+        persistent_login
+      ]
+    );
+    # activate plugins
+    plugins = [
+      "persistent_login"
+      "managesieve" # built-in
+    ];
+    dicts = with pkgs.aspellDicts; [
+      # https://search.nixos.org/packages?query=aspellDicts
+      en
+    ];
+    maxAttachmentSize = config.mailserver.messageSizeLimit / 1024 / 1024;
+    extraConfig = ''
+      $config['imap_host'] = "ssl://${config.mailserver.fqdn}";
+      $config['smtp_host'] = "ssl://${config.mailserver.fqdn}";
+      $config['smtp_user'] = "%u";
+      $config['smtp_pass'] = "%p";
+
+      $config['managesieve_host'] = "tls://${config.mailserver.fqdn}";
+      $config['managesieve_port'] = 4190;
+      $config['managesieve_usetls'] = true;
+    '';
+  };
+
+  services.nginx.virtualHosts.${config.services.roundcube.hostName} = {
+    enableACME = true;
+    forceSSL = true;
+  };
+
+  networking.firewall.allowedTCPPorts = [
+    80
+    443
+  ];
+}

docs/roundcube.rst

@@ -0,0 +1,26 @@
+Roundcube
+=========
+
+Roundcube is a browser-based open-source webmail client that provides a
+full-featured email interface with support for IMAP, SMTP, address books, and
+extensible plugins.
+
+Code
+^^^^
+
+The NixOS module for Roundcube integrates almost immediately with NixOS
+mailserver, automatically configuring an Nginx virtual host and ACME-managed
+TLS for secure webmail access; using other web servers may require additional
+manual setup.
+
+Once set up you can login with your login account credentials.
+
+.. literalinclude:: ./roundcube.nix
+   :language: nix
+
+To use a different reverse proxy, such as Caddy, bind Roundcube's Nginx virtual
+host to ``127.0.0.1`` on a custom port and disable SSL and ACME, as the reverse
+proxy will handle those.
+
+.. literalinclude:: ./roundcube-caddy.nix
+   :language: nix

docs/rspamd-tuning.rst

@@ -44,9 +44,10 @@ details the meaning of each symbol. You can tune the weight if a symbol if neede
 
   services.rspamd.locals = {
     "groups.conf".text = ''
-      symbols {
-        "FORGED_RECIPIENTS" { weight = 0; }
-      }'';
+      symbols "FORGED_RECIPIENTS" {
+        weight = 0;
+      }
+    '';
   };
 
 Tune action thresholds
@@ -93,7 +94,7 @@ With an nginx reverse-proxy
 
 If you have a secured nginx reverse proxy set on the host, you can use it to expose the socket.
 **Keep in mind the UI is unsecured by default, you need to setup an authentication scheme**, for
-exemple with `basic auth <https://docs.nginx.com/nginx/admin-guide/security-controls/configuring-http-basic-authentication/>`_:
+example with `basic auth <https://docs.nginx.com/nginx/admin-guide/security-controls/configuring-http-basic-authentication/>`_:
 
 .. code:: nix
 

docs/setup-example.nix

@@ -0,0 +1,58 @@
+{
+  config,
+  ...
+}:
+{
+  imports = [
+    (builtins.fetchTarball {
+      # This is a quick and dirty way to import a NixOS mailserver release. What
+      # you should do long-term is use a proper dependency pinning tool like npins
+      # or flakes.
+
+      # URL to the tarball for the release matching your NixOS release
+      url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-26.05/nixos-mailserver-nixos-26.05.tar.gz";
+
+      # Hash of the unpacked tarball, run the following command to retrieve it
+      # release="nixos-26.05" nix-prefetch-url "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/${release}/nixos-mailserver-${release}.tar.gz" --unpack
+      sha256 = "0000000000000000000000000000000000000000000000000000";
+    })
+  ];
+
+  # https://letsencrypt.org/repository/#let-s-encrypt-subscriber-agreement
+  security.acme.acceptTerms = true;
+
+  # Allow incoming HTTP connections
+  networking.firewall.allowedTCPPorts = [ 80 ];
+
+  # Enable ACME HTTP-01 challenge with nginx
+  services.nginx = {
+    enable = true;
+    virtualHosts.${config.mailserver.fqdn}.enableACME = true;
+  };
+
+  mailserver = {
+    enable = true;
+    stateVersion = 5;
+    fqdn = "mail.example.com";
+    domains = [ "example.com" ];
+
+    # Reference the existing ACME configuration created by nginx
+    x509.useACMEHost = config.mailserver.fqdn;
+
+    # A list of all login accounts. To create the password hashes, use
+    # nix-shell -p mkpasswd --run 'mkpasswd -s'
+    accounts = {
+      "user1@example.com" = {
+        # Reads the password hash from a file on the server
+        hashedPasswordFile = "/a/file/containing/a/hashed/password";
+
+        # Additional addresses delivered to this mailbox
+        aliases = [ "postmaster@example.com" ];
+      };
+      "user2@example.com" = {
+        # Provides the password hash inline
+        hashedPassword = "$y$j9T$JqqefR6flaaJBRjD4KVZc1$QM6h4Spr5.yn/FuIT.ydTV22daEbiVd8ZprV/POtPgB";
+      };
+    };
+  };
+}

docs/setup-guide.rst

@@ -1,3 +1,5 @@
+.. _setup-guide:
+
 Setup Guide
 ===========
 
@@ -5,235 +7,306 @@ Mail servers can be a tricky thing to set up. This guide is supposed to
 run you through the most important steps to achieve a 10/10 score on
 `<https://mail-tester.com>`_.
 
-What you need is:
+Requirements
+~~~~~~~~~~~~
 
-- a server running NixOS with a public IP
-- a domain name.
+To set up a self-hosted mail server, you need the following:
+
+* Small (e.g. 1C/2G) server running NixOS
+* Stable IPv4 and - strongly recommended - IPv6 addresses
+
+  * Ability to configure a Reverse DNS (PTR record) for your IP addresses
+  * Access to SMTP traffic on port 25/tcp - some hosters make you ask for this
+
+* A registered domain name with DNS record management access
+
+Once these requirements are in place, you can begin setting up your selfhosted
+mailserver.
 
 .. note::
 
-   In the following, we consider a server with the public IP ``1.2.3.4``
-   and the domain ``example.com``.
+   Below we'll assume that your server got assigned the public IP addresses
+   ``192.0.2.1`` (IPv4) and ``2001:db8::1`` (IPv6) and that you control the
+   ``example.com`` domain.
 
-First, we will set the minimum DNS configuration to be able to deploy
-an up and running mail server. Once the server is deployed, we could
-then set all DNS entries required to send and receive mails on this
-server.
+Configure forward DNS records
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Setup DNS A/AAAA records for server
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Here we set up ``mail.example.com`` as the forward hostname for your mail server
+to point to the IP addresses allocated to the server. This allows reaching
+the server under this name and to reference it later in MX records for mail
+delivery.
 
-Add DNS records to the domain ``example.com`` with the following
-entries
+Now edit the ``example.com`` zone and create the following DNS records:
 
-==================== ===== ==== =============
-Name (Subdomain)     TTL   Type Value
-==================== ===== ==== =============
-``mail.example.com`` 10800 A    ``1.2.3.4``
-``mail.example.com`` 10800 AAAA ``2001::1``
-==================== ===== ==== =============
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
 
-If your server does not have an IPv6 address, you must skip the `AAAA` record.
+   mail.example.com., 3600, A, 192.0.2.1
+   mail.example.com., 3600, AAAA, 2001:db8::1
 
-You can check this with
+.. note::
+   If your server does not have an IPv6 address, you must skip the ``AAAA``
+   record.
 
-::
+Verify DNS record propagation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-   $ nix-shell -p bind --command "host -t A mail.example.com"
-   mail.example.com has address 1.2.3.4
+Before we continue with the next step, we require that the forward DNS record
+has propagated. For that it's best to check an authoritative nameserver for
+``example.com`` so that we don't look at cached DNS records.
 
-   $ nix-shell -p bind --command "host -t AAAA mail.example.com"
-   mail.example.com has address 2001::1
+.. code-block:: console
 
-Note that it can take a while until a DNS entry is propagated. This
-DNS entry is required for the Let's Encrypt certificate generation
-(which is used in the below configuration example).
+   # Find the authoritative nameservers for example.com
+   $ nix-shell -p dig --command "dig NS example.com +short"
+   ns1.example.org.
+   ns2.example.org.
+
+   # Query the A record from an authoritative nameserver
+   $ nix-shell -p dig --command "dig @ns1.example.org A mail.example.com +short"
+   192.0.2.1
+
+   # Query the AAAA record from an authoritative nameserver
+   $ nix-shell -p dig --command "dig @ns1.example.org AAAA mail.example.com +short"
+   2001:db8::1
+
+
+DNS propagation usually takes a few minutes, so you might need to retry these
+queries. Once the IP addresses appear you can continue with the next step.
 
 Setup the server
 ~~~~~~~~~~~~~~~~
 
-The following describes a server setup that is fairly complete. Even
-though there are more possible options (see the `NixOS Mailserver
-options documentation <options.html>`_), these should be the most
-common ones.
+The following configuration describes a fairly complete mail server, capable
+of sending and receiving mail for statically configured accounts. It includes
+encrypted SMTP and IMAP services for secure delivery and retrieval, and relies
+on ACME HTTP-01 to automatically obtain and maintain a TLS certificate.
 
-.. code:: nix
+While `more options`_ are available, the configuration below covers the most
+common settings to get your mail server up and running.
 
-   { config, pkgs, ... }: {
-     imports = [
-       (builtins.fetchTarball {
-         # Pick a release version you are interested in and set its hash, e.g.
-         url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-25.05/nixos-mailserver-nixos-25.05.tar.gz";
-         # To get the sha256 of the nixos-mailserver tarball, we can use the nix-prefetch-url command:
-         # release="nixos-25.05"; nix-prefetch-url "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/${release}/nixos-mailserver-${release}.tar.gz" --unpack
-         sha256 = "0000000000000000000000000000000000000000000000000000";
-       })
-     ];
+.. _more options: options.html
 
-     mailserver = {
-       enable = true;
-       fqdn = "mail.example.com";
-       domains = [ "example.com" ];
+.. literalinclude:: ./setup-example.nix
+   :language: nix
 
-       # A list of all login accounts. To create the password hashes, use
-       # nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
-       loginAccounts = {
-         "user1@example.com" = {
-           hashedPasswordFile = "/a/file/containing/a/hashed/password";
-           aliases = ["postmaster@example.com"];
-         };
-         "user2@example.com" = { ... };
-       };
+After a ``nixos-rebuild switch`` your server should be running all the necessary
+mail services.
 
-       # Use Let's Encrypt certificates. Note that this needs to set up a stripped
-       # down nginx and opens port 80.
-       certificateScheme = "acme-nginx";
-     };
-     security.acme.acceptTerms = true;
-     security.acme.defaults.email = "security@example.com";
-   }
+Configure DNS records
+~~~~~~~~~~~~~~~~~~~~~
 
-After a ``nixos-rebuild switch`` your server should be running all
-mail components.
+Reverse DNS
+^^^^^^^^^^^
 
-Setup all other DNS requirements
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Earlier, we configured forward DNS from your hostname to your IP address. Now we
+will configure reverse DNS so that your IP address points back to your hostname.
 
-Set rDNS (reverse DNS) entry for server
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+If your forward and reverse DNS do not match, many mail servers will reject or
+flag your emails as spam, severely impairing delivery.
 
-Wherever you have rented your server, you should be able to set reverse
-DNS entries for the IP’s you own:
+Your server provider should allow you to configure reverse DNS (PTR record)
+records for the IP addresses you control, typically through their control panel
+or account management interface:
 
-- Add an entry resolving IPv4 address ``1.2.3.4`` to ``mail.example.com``.
-- Add an entry resolving IPv6 ``2001::1`` to ``mail.example.com``. Again, this
-  must be skipped if your server does not have an IPv6 address.
+- Configure ``192.0.2.1`` to point to ``mail.example.com.``
+- Configure ``2001:db8::1`` to point to ``mail.example.com.``, if you have IPv6
+  addressing
+
+Alternatively, if you interact with a proper DNS setup, the actual DNS records
+look like this:
+
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
+
+   1.2.0.192.in-addr.arpa., 86400, PTR, mail.example.com.
+   1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa., 86400, PTR, mail.example.com.
+
+.. note::
+   Reverse DNS uses reverse notation for naming its records:
+
+   * IPv4 reverses the order of the octets and appends ``in-addr.arpa.``, so
+     ``192.0.2.1`` becomes ``1.2.0.192.in-addr.arpa.``
+   * IPv6 fully expands the address and reverses each hex digit before
+     concatenating it with dots and appending ``ip6.arpa.``
+
+   .. code-block:: console
+
+      nix-shell -p haskellPackages.ip6addr --command "ip6addr --ptr 2001:db8::1"
+      1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.IP6.ARPA.
 
 .. warning::
 
-   We don't recommend setting up a mail server if you are not able to
-   set a reverse DNS on your public IP because sent emails would be
-   mostly marked as spam. Note that many residential ISP providers
-   don't allow you to set a reverse DNS entry.
+   We don't recommend setting up a mail server if you are unable to configure
+   reverse DNS on your public IP addresses because mails would inevitable be
+   marked as spam. Note that many residential ISP providers don't allow you to
+   set a reverse DNS entry and prohibit sending mail through policy blocklists
+   like Spamhaus PBL.
 
-You can check this with
+DNS propagation often isn't instant, so verify before continuing:
 
-::
+.. code-block:: console
 
-   $ nix-shell -p bind --command "host 1.2.3.4"
-   4.3.2.1.in-addr.arpa domain name pointer mail.example.com.
+   $ nix-shell -p dig --command "dig -x 192.0.2.1 +short"
+   mail.example.com.
 
-   $ nix-shell -p bind --command "host 2001::1"
-   1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.2.ip6.arpa domain name pointer mail.example.com.
-
-Note that it can take a while until a DNS entry is propagated.
-
-Set a ``MX`` record
-^^^^^^^^^^^^^^^^^^^
+   $ nix-shell -p dig --command "dig -x 2001:db8::1 +short"
+   mail.example.com.
 
 
-Add a ``MX`` record to the domain ``example.com``.
+MX record
+^^^^^^^^^
 
-================ ==== ======== =================
-Name (Subdomain) Type Priority Value
-================ ==== ======== =================
-example.com      MX   10       mail.example.com
-================ ==== ======== =================
+The MX record instructs other mailservers where to deliver mail for a domain
+name.
 
-You can check this with
+Create the MX record for ``example.com`` to point to the hostname of the server.
 
-::
+.. csv-table::
+   :header: "Name", "TTL", "Priority", "Type", "Value"
+   :widths: 30, 10, 10, 10, 50
 
-   $ nix-shell -p bind --command "host -t mx example.com"
-   example.com mail is handled by 10 mail.example.com.
+   example.com., 3600, MX, 10, mail.example.com.
 
-Note that it can take a while until a DNS entry is propagated.
+The priority field determines the order when multiple servers are configured.
+It is not important in this scenario but setting a value is mandatory and 10
+leaves some wiggle room below and above, should you ever need that.
 
-Set a ``SPF`` record
-^^^^^^^^^^^^^^^^^^^^
+.. code-block:: console
 
-Add a `SPF <https://en.wikipedia.org/wiki/Sender_Policy_Framework>`_
-record to the domain ``example.com``.
+   $ nix-shell -p dig --command "dig @ns1.example.org MX example.com +short"
+   10 mail.example.com.
 
-================ ===== ==== ================================
-Name (Subdomain) TTL   Type Value
-================ ===== ==== ================================
-example.com      10800 TXT  `v=spf1 a:mail.example.com -all`
-================ ===== ==== ================================
+SPF record
+^^^^^^^^^^
 
-You can check this with
+With `SPF`_ we can specify which mail servers are authorized to send mail on
+behalf of a domain name.
 
-::
+.. _SPF: https://en.wikipedia.org/wiki/Sender_Policy_Framework
 
-   $ nix-shell -p bind --command "host -t TXT example.com"
-   example.com descriptive text "v=spf1 a:mail.example.com -all"
+The SPF record is TXT record and we can tie it in with the MX record we created
+in the previous step. Finishing with ``-all`` indicates that without any match
+the mail should be rejected.
 
-Note that it can take a while until a DNS entry is propagated.
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
 
-Set ``DKIM`` signature
-^^^^^^^^^^^^^^^^^^^^^^
+   example.com., 86400, TXT, v=spf1 mx -all
 
-On your server, the ``rspamd`` systemd service generated a file
-containing your DKIM public key in the file
-``/var/dkim/example.com.mail.txt``. The content of this file looks
-like
+.. code-block:: console
 
-::
+   $ nix-shell -p dig --command "dig TXT example.com +short"
+   v=spf1 mx -all
 
-   mail._domainkey	IN	TXT	( "v=DKIM1; k=rsa; "
-      "p=<really-long-key>" )  ; ----- DKIM key mail for nixos.org
 
-where ``really-long-key`` is your public key.
+DKIM record
+^^^^^^^^^^^
 
-Based on the content of this file, we can add a ``DKIM`` record to the
-domain ``example.com``.
+On system activation a `DKIM`_ keypair for ``example.com`` was generated. The
+mail server uses this key to sign outgoing emails, allowing receiving servers to
+verify the authenticity of the sender domain and ensuring that the signed parts
+of the message have not been tampered with.
 
-=========================== ===== ==== ================================================
-Name (Subdomain)            TTL   Type Value
-=========================== ===== ==== ================================================
-mail._domainkey.example.com 10800 TXT  ``v=DKIM1; k=rsa; s=email; p=<really-long-key>``
-=========================== ===== ==== ================================================
+.. _DKIM: https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail
 
-You can check this with
+Now, check ``/var/dkim/example.com.mail.txt``, which contains the proposed DNS
+record for the ``mail`` DKIM selector.
 
-::
+.. code-block:: none
 
-   $ nix-shell -p bind --command "host -t txt mail._domainkey.example.com"
-   mail._domainkey.example.com descriptive text "v=DKIM1;p=<really-long-key>"
+   mail._domainkey IN TXT ( "v=DKIM1; k=rsa; "
+    "p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAv7hSess/UgEjaaq/NDn5KtW2iZzYljhf45DH3tN/kqcJ04JJk/Z1rS7CMJQ/pYZSSnQOju0H25uOtODvhqXPDxDdtCyDSrx54z/38lGNtA76/iWy/ikjb9hEkb2k3HuKex3P4KhhOC1pytDEFnh/T2aBxPNOigc/cpqm1U9RbnAwvArtx9dgOAgiV8rOIgPgyrPw1B3cJG3hgFYU2"
+    "GwXMoiFQPgwm7bkjelmThqXozA7jFJfnYt49jjrIYCv8X/nQx9cNpVAv2852mhU/3uuy6sa4MPjT6RiK9BJCMyDnqSpTPCjIubL4VhGCuzp7RPBkayWnlaH0X8PWGq6BQ0eBwIDAQAB"
+   ) ;
 
-Note that it can take a while until a DNS entry is propagated.
+Based on the content of this file, we can create the DKIM TXT record for the
+``mail`` selector in the ``example.com`` zone. For the ``p=`` value, glue the
+two long strings back together without any quotes and spaces and put them into
+your record below.
 
-Set a ``DMARC`` record
-^^^^^^^^^^^^^^^^^^^^^^
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
 
-Add a ``DMARC`` record to the domain ``example.com``.
+   mail._domainkey.example.com., 86400, TXT, v=DKIM1; k=rsa; p=MIIBIjANBgk...Q0eBwIDAQAB
 
-======================== ===== ==== ====================
-Name (Subdomain)         TTL   Type Value
-======================== ===== ==== ====================
-_dmarc.example.com       10800 TXT  ``v=DMARC1; p=none``
-======================== ===== ==== ====================
+.. code-block:: console
 
-You can check this with
+   $ nix-shell -p dig --command "dig @ns1.example.org TXT mail._domainkey.example.com +short"
+   "v=DKIM1; k=rsa; p=MIIBIjANBgk...Q0eBwIDAQAB"
 
-::
 
-   $ nix-shell -p bind --command "host -t TXT _dmarc.example.com"
-   _dmarc.example.com descriptive text "v=DMARC1; p=none"
+DMARC record
+^^^^^^^^^^^^
 
-Note that it can take a while until a DNS entry is propagated.
+Finally, DMARC lets you define a policy for how strictly SPF and DKIM should be
+checked and how to handle validation failures. For a new server, it’s important
+to have a DMARC record in place, even if it doesn’t enforce any actions yet,
+because it improves deliverability by showing receiving servers that your domain
+is properly managed and reducing the risk of email spoofing.
+
+.. csv-table::
+   :header: "Name", "TTL", "Type", "Value"
+   :widths: 30, 10, 10, 50
+
+   _dmarc.example.com., 86400, TXT, v=DMARC1; p=none;
+
+Verify propagation one final time.
+
+.. code-block:: console
+
+   $ nix-shell -p dig --command "dig @ns1.example.org TXT _dmarc.example.com +short"
+   "v=DMARC1; p=none"
 
 
 Test your Setup
 ~~~~~~~~~~~~~~~
 
-Write an email to your aunt (who has been waiting for your reply far too
-long), and sign up for some of the finest newsletters the Internet has.
-Maybe you want to sign up for the `SNM Announcement
-List <https://www.freelists.org/list/snm>`__?
+Write an email to your aunt — she’s been waiting far too long for your reply,
+and this is your chance to finally make her day. Or, if you prefer a less
+emotional test, send a message to `mail-tester.com`_ to see how your outgoing
+mail scores.
 
-Besides that, you can send an email to
-`mail-tester.com <https://www.mail-tester.com/>`__ and see how you
-score, and let `mxtoolbox.com <http://mxtoolbox.com/>`__ take a look at
-your setup, but if you followed the steps closely then everything should
-be awesome!
+You can also let `MXToolbox`_ take a peek at your setup. If you followed the
+steps carefully, everything should be working perfectly!
+
+.. _mail-tester.com: https://mail-tester.com/
+.. _MXToolbox: https://mxtoolbox.com/
+
+
+Join the community
+~~~~~~~~~~~~~~~~~~
+
+The community has a lively chat room on Matrix at `#nixos-mailserver:nixos.org`_
+where you can ask questions, get help, share ideas, or discuss contributions.
+
+.. _#nixos-mailserver:nixos.org: https://matrix.to/#/#nixos-mailserver:nixos.org
+
+Next steps
+~~~~~~~~~~
+
+Your server scored perfect results already, so these steps are entirely
+optional.
+
+Are you feeling adventurous? Dive into our `advanced configurations`_ to explore
+additional features and capabilities that let you fine-tune and extend your
+mail setup.
+
+If you want to take things even further, more elaborate testing services can
+give you a clearer picture of your mail service and suggest ways to improve
+it.
+
+- `internet.nl`_ (supported by the Dutch Government)
+- `MECSA`_ (supported by the European Commission)
+
+Finally, you can also browse the full list of `options`_ provided by NixOS mailserver.
+
+.. _advanced configurations: advanced-configurations.html
+.. _options: options.html
+.. _internet.nl: https://internet.nl/test-mail/
+.. _MECSA: https://mecsa.jrc.ec.europa.eu/

docs/srs.rst

@@ -0,0 +1,102 @@
+Sender Rewriting Scheme
+=======================
+
+The Sender Rewriting Scheme (SRS) allows mail servers to forward emails without
+breaking SPF checks. By rewriting the envelope sender to an address within the
+forwarder’s domain, SRS ensures that forwarded messages pass SPF validation,
+preventing them from being rejected as spoofed or unauthorized.
+
+How SRS works in practice
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+1. ``alice@foo.example`` receives an E-Mail from ``bob@bar.example``. Both the
+envelope sender as well as the ``From`` header show ``bob@bar.example``. This
+results in strict SPF alignment, because ``bar.example`` is the domain used in
+both the ``Return-Path`` and ``FROM`` headers.
+
+2. ``alice@foo.example`` forwards the mail to ``charlie@moo.example`` and
+uses SRS to rewrite the envelope sender to originate from the local SRS domain
+(e.g. `SRS0=HHH=TT=bar.example=alice@foo.example`). The ``FROM`` header remains
+unchanged. This ensures that the forwarded mail succeeds SPF checks.
+
+3. The email reaches ``charlie@moo.example``. SPF passes because the sender
+domain in the envelope has been rewritten. The mismatch between envelope sender
+domain and ``FROM`` domain does however break strict SPF alignment.
+
+Enabling SRS
+~~~~~~~~~~~~
+
+In a simple setup just enabling SRS will use your ``mailserver.systemDomain``
+when rewriting the envelope sender domain.
+
+.. code:: nix
+
+  {
+    mailserver = {
+      srs = {
+        enable = true;
+        #domain = "srs.example.com";
+      };
+    };
+  };
+..
+
+While you can reuse an existing email domain for SRS, it is recommended to
+configure a dedicated SRS domain. This is particularly important under the
+following conditions:
+
+* Multiple unrelated mail domains are hosted on the mailserver
+* The mail domain requires strict SPF alignment in its DMARC policy
+
+Required DNS changes
+~~~~~~~~~~~~~~~~~~~~
+
+.. note::
+  In the following example we assume that you want to set up a dedicated SRS
+  domain. If that is not the case you already have SPF and DKIM set up for the
+  system domain. If you have a DMARC record on the system domain, make sure it
+  uses a relaxed SPF alignment policy (``aspf=r``).
+
+First we set up an MX record. This is so that we can receive and route bounces
+that can result from forwards.
+
+======================== ===== ==== ======== =====================
+Name (Subdomain)         TTL   Type Priority Value
+======================== ===== ==== ======== =====================
+srs.example.com          10800 MX   10       ``mail.example.com``
+======================== ===== ==== ==============================
+
+Next up is the SPF record on the SRS domain to allow SPF authentication.
+
+======================== ===== ==== ===================
+Name (Subdomain)         TTL   Type Value
+======================== ===== ==== ===================
+srs.example.com          10800 TXT  ``v=spf1 mx -all``
+======================== ===== ==== ===================
+
+Then we deploy the DKIM record with the `p=<value>` taken from
+``/var/dkim/srs.example.com.mail.txt``, that appears after deploying with SRS
+enabled.
+
+=============================== ===== ==== ========================================
+Name (Subdomain)                TTL   Type Value
+=============================== ===== ==== ========================================
+mail._domainkey.srs.example.com 10800 TXT  ``v=DKIM1; k=rsa; p=<really-long-key>``
+=============================== ===== ==== ========================================
+
+Finally we can tie this together in the DMARC record to require receivers to
+verify the requested SPF/DKIM alignment.
+
+.. note::
+
+   The SRS domain can only support relaxed SPF alignment due to the envelope
+   sender and ``FROM`` header mismatch.
+
+======================== ===== ==== =========================================
+Name (Subdomain)         TTL   Type Value
+======================== ===== ==== =========================================
+_dmarc.srs.example.com   10800 TXT  ``v=DMARC1; p=reject; aspf=r; adkim=s;``
+======================== ===== ==== =========================================
+
+We can safely configure a ``reject`` policy on the SRS domain, to enforce the
+SPF and DKIM alignment as configured above.

flake.lock

@@ -19,15 +19,15 @@
     "flake-compat": {
       "flake": false,
       "locked": {
-        "lastModified": 1747046372,
-        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
-        "owner": "edolstra",
+        "lastModified": 1767039857,
+        "narHash": "sha256-vNpUSpF5Nuw8xvDLj2KCwwksIbjua2LZCqhV1LNRDns=",
+        "owner": "NixOS",
         "repo": "flake-compat",
-        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "rev": "5edf11c44bc78a0d334f6334cdaf7d60d732daab",
         "type": "github"
       },
       "original": {
-        "owner": "edolstra",
+        "owner": "NixOS",
         "repo": "flake-compat",
         "type": "github"
       }
@@ -43,11 +43,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1742649964,
-        "narHash": "sha256-DwOTp7nvfi8mRfuL1escHDXabVXFGT1VlPD1JHrtrco=",
+        "lastModified": 1778507602,
+        "narHash": "sha256-kTwur1wV+01SdqskVMSo6JMEpg71ps3HpbFY2GsflKs=",
         "owner": "cachix",
         "repo": "git-hooks.nix",
-        "rev": "dcf5072734cb576d2b0c59b2ac44f5050b5eac82",
+        "rev": "61ab0e80d9c7ab14c256b5b453d8b3fb0189ba0a",
         "type": "github"
       },
       "original": {
@@ -79,32 +79,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1747179050,
-        "narHash": "sha256-qhFMmDkeJX9KJwr5H32f1r7Prs7XbQWtO0h3V0a0rFY=",
+        "lastModified": 1779622335,
+        "narHash": "sha256-ViA62qtL5za7V3d5I8OA9q9JcFhsVAiL5jVHwEclWqk=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "adaa24fbf46737f3f1b5497bf64bae750f82942e",
+        "rev": "705e9929918b43bd7b715dc0a878ac870449bb03",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-25_05": {
-      "locked": {
-        "lastModified": 1747610100,
-        "narHash": "sha256-rpR5ZPMkWzcnCcYYo3lScqfuzEw5Uyfh+R0EKZfroAc=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "ca49c4304acf0973078db0a9d200fd2bae75676d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-25.05",
+        "ref": "nixos-26.05-small",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -114,8 +98,7 @@
         "blobs": "blobs",
         "flake-compat": "flake-compat",
         "git-hooks": "git-hooks",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-25_05": "nixpkgs-25_05"
+        "nixpkgs": "nixpkgs"
       }
     }
   },

flake.nix

@@ -4,7 +4,7 @@
   inputs = {
     flake-compat = {
       # for shell.nix compat
-      url = "github:edolstra/flake-compat";
+      url = "github:NixOS/flake-compat";
       flake = false;
     };
     git-hooks = {
@@ -12,182 +12,211 @@
       inputs.flake-compat.follows = "flake-compat";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    nixpkgs-25_05.url = "github:NixOS/nixpkgs/nixos-25.05";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05-small";
     blobs = {
       url = "gitlab:simple-nixos-mailserver/blobs";
       flake = false;
     };
   };
 
-  outputs = { self, blobs, git-hooks, nixpkgs, nixpkgs-25_05, ... }: let
-    lib = nixpkgs.lib;
-    system = "x86_64-linux";
-    pkgs = nixpkgs.legacyPackages.${system};
-    releases = [
-      {
-        name = "unstable";
-        nixpkgs = nixpkgs;
-        pkgs = nixpkgs.legacyPackages.${system};
-      }
-      {
-        name = "25.05";
-        nixpkgs = nixpkgs-25_05;
-        pkgs = nixpkgs-25_05.legacyPackages.${system};
-      }
-    ];
-    testNames = [
-      "clamav"
-      "external"
-      "internal"
-      "ldap"
-      "multiple"
-    ];
+  outputs =
+    {
+      self,
+      blobs,
+      git-hooks,
+      nixpkgs,
+      ...
+    }:
+    let
+      lib = nixpkgs.lib;
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+      releases = [
+        {
+          name = "unstable";
+          nixpkgs = nixpkgs;
+          pkgs = nixpkgs.legacyPackages.${system};
+        }
+      ];
+      testNames = [
+        "clamav"
+        "external"
+        "internal"
+        "ldap"
+        "multiple"
+      ];
 
-    genTest = testName: release: let
-      pkgs = release.pkgs;
-      nixos-lib = import (release.nixpkgs + "/nixos/lib") {
-        inherit (pkgs) lib;
-      };
-    in {
-      name = "${testName}-${builtins.replaceStrings ["."] ["_"] release.name}";
-      value = nixos-lib.runTest {
-        hostPkgs = pkgs;
-        imports = [ ./tests/${testName}.nix ];
-        _module.args = { inherit blobs; };
-        extraBaseModules.imports = [ ./default.nix ];
-      };
-    };
-
-    # Generate an attribute set such as
-    # {
-    #   external-unstable = <derivation>;
-    #   external-21_05 = <derivation>;
-    #   ...
-    # }
-    allTests = lib.listToAttrs (
-      lib.flatten (map (t: map (r: genTest t r) releases) testNames));
-
-    mailserverModule = import ./.;
-
-    # Generate a MarkDown file describing the options of the NixOS mailserver module
-    optionsDoc = let
-      eval = lib.evalModules {
-        modules = [
-          mailserverModule
-          {
-            _module.check = false;
-            mailserver = {
-              fqdn = "mx.example.com";
-              domains = [
-                "example.com"
-              ];
-              dmarcReporting = {
-                organizationName = "Example Corp";
-                domain = "example.com";
-              };
-            };
-          }
-        ];
-      };
-      options = builtins.toFile "options.json" (builtins.toJSON
-        (lib.filter (opt: opt.visible && !opt.internal && lib.head opt.loc == "mailserver")
-          (lib.optionAttrSetToDocList eval.options)));
-    in pkgs.runCommand "options.md" { buildInputs = [pkgs.python3Minimal]; } ''
-      echo "Generating options.md from ${options}"
-      python ${./scripts/generate-options.py} ${options} > $out
-      echo $out
-    '';
-
-    documentation = pkgs.stdenv.mkDerivation {
-      name = "documentation";
-      src = lib.sourceByRegex ./docs ["logo\\.png" "conf\\.py" "Makefile" ".*\\.rst"];
-      buildInputs = [(
-        pkgs.python3.withPackages (p: with p; [
-          sphinx
-          sphinx_rtd_theme
-          myst-parser
-          linkify-it-py
-        ])
-      )];
-      buildPhase = ''
-        cp ${optionsDoc} options.md
-        # Workaround for https://github.com/sphinx-doc/sphinx/issues/3451
-        unset SOURCE_DATE_EPOCH
-        make html
-      '';
-      installPhase = ''
-        cp -Tr _build/html $out
-      '';
-    };
-
-  in {
-    nixosModules = rec {
-      mailserver = mailserverModule;
-      default = mailserver;
-    };
-    nixosModule = self.nixosModules.default; # compatibility
-    hydraJobs.${system} = allTests // {
-      inherit documentation;
-      inherit (self.checks.${system}) pre-commit;
-    };
-    checks.${system} = allTests // {
-      pre-commit = git-hooks.lib.${system}.run {
-        src = ./.;
-        hooks = {
-          # docs
-          markdownlint = {
-            enable = true;
-            settings.configuration = {
-              # Max line length, doesn't seem to correclty account for lines containing links
-              # https://github.com/DavidAnson/markdownlint/blob/main/doc/md013.md
-              MD013 = false;
-            };
+      genTest =
+        testName: release:
+        let
+          pkgs = release.pkgs;
+          nixos-lib = import (release.nixpkgs + "/nixos/lib") {
+            inherit (pkgs) lib;
           };
-          rstcheck = {
-            enable = true;
-            package = pkgs.rstcheckWithSphinx;
-            entry = lib.getExe pkgs.rstcheckWithSphinx;
-            files = "\\.rst$";
+        in
+        {
+          name = "${testName}-${builtins.replaceStrings [ "." ] [ "_" ] release.name}";
+          value = nixos-lib.runTest {
+            hostPkgs = pkgs;
+            imports = [ ./tests/${testName}.nix ];
+            _module.args = { inherit blobs; };
+            extraBaseModules.imports = [ ./default.nix ];
           };
+        };
 
-          # nix
-          deadnix.enable = true;
+      # Generate an attribute set such as
+      # {
+      #   external-unstable = <derivation>;
+      #   external-21_05 = <derivation>;
+      #   ...
+      # }
+      allTests = lib.listToAttrs (lib.flatten (map (t: map (r: genTest t r) releases) testNames));
 
-          # python
-          pyright.enable = true;
-          ruff = {
-            enable = true;
-            args = [
-              "--extend-select"
-              "I"
+      mailserverModule = import ./.;
+
+      # Generate a MarkDown file describing the options of the NixOS mailserver module
+      optionsDoc =
+        let
+          eval = lib.evalModules {
+            modules = [
+              mailserverModule
+              {
+                _module.check = false;
+                mailserver = {
+                  fqdn = "mx.example.com";
+                  systemDomain = "example.com";
+                  domains = [
+                    "example.com"
+                  ];
+                };
+              }
             ];
           };
-          ruff-format.enable = true;
+          options = builtins.toFile "options.json" (
+            builtins.toJSON (
+              lib.filter (opt: opt.visible && !opt.internal && lib.head opt.loc == "mailserver") (
+                lib.optionAttrSetToDocList eval.options
+              )
+            )
+          );
+        in
+        pkgs.runCommand "options.md" { buildInputs = [ pkgs.python3Minimal ]; } ''
+          echo "Generating options.md from ${options}"
+          python ${./scripts/generate-options.py} ${options} > $out
+          echo $out
+        '';
 
-          # scripts
-          shellcheck.enable = true;
+      documentation = pkgs.stdenv.mkDerivation {
+        name = "documentation";
+        src = lib.sourceByRegex ./docs [
+          "logo\\.png"
+          "conf\\.py"
+          "Makefile"
+          ".*\\.nix"
+          ".*\\.rst"
+        ];
+        buildInputs = [
+          (pkgs.python3.withPackages (
+            p: with p; [
+              sphinx
+              sphinx-rtd-theme
+              myst-parser
+              linkify-it-py
+            ]
+          ))
+        ];
+        buildPhase = ''
+          cp ${optionsDoc} options.md
+          # Workaround for https://github.com/sphinx-doc/sphinx/issues/3451
+          unset SOURCE_DATE_EPOCH
+          make html
+        '';
+        installPhase = ''
+          cp -Tr _build/html $out
+        '';
+      };
 
-          # sieve
-          check-sieve = {
-            enable = true;
-            package = pkgs.check-sieve;
-            entry = lib.getExe pkgs.check-sieve;
-            files = "\\.sieve$";
+    in
+    {
+      nixosModules = rec {
+        mailserver = mailserverModule;
+        default = mailserver;
+      };
+      nixosModule = self.nixosModules.default; # compatibility
+      hydraJobs.${system} = allTests // {
+        inherit documentation;
+        inherit (self.checks.${system}) pre-commit;
+      };
+      checks.${system} = allTests // {
+        pre-commit = git-hooks.lib.${system}.run {
+          src = ./.;
+          package = pkgs.prek;
+          hooks = {
+            # docs
+            markdownlint = {
+              enable = true;
+              settings.configuration = {
+                # Max line length, doesn't seem to correctly account for lines containing links
+                # https://github.com/DavidAnson/markdownlint/blob/main/doc/md013.md
+                MD013 = false;
+              };
+            };
+            rstcheck = {
+              enable = true;
+              package = pkgs.rstcheckWithSphinx;
+              entry = lib.getExe pkgs.rstcheckWithSphinx;
+              files = "\\.rst$";
+            };
+
+            # spell checking
+            typos = {
+              enable = true;
+              settings.configPath = ".typos.toml";
+            };
+
+            # nix
+            deadnix.enable = true;
+            nixfmt.enable = true;
+
+            # python
+            pyright.enable = true;
+            ruff = {
+              enable = true;
+              args = [
+                "--extend-select"
+                "I"
+              ];
+            };
+            ruff-format.enable = true;
+
+            # scripts
+            shellcheck.enable = true;
+
+            # sieve
+            check-sieve = {
+              enable = true;
+              package = pkgs.check-sieve;
+              entry = lib.getExe pkgs.check-sieve;
+              files = "\\.sieve$";
+            };
           };
         };
       };
+      packages.${system} = {
+        inherit optionsDoc documentation;
+      };
+      devShells.${system}.default = pkgs.mkShellNoCC {
+        inputsFrom = [ documentation ];
+        packages =
+          with pkgs;
+          [
+            glab
+          ]
+          ++ self.checks.${system}.pre-commit.enabledPackages;
+        shellHook = self.checks.${system}.pre-commit.shellHook;
+      };
+      devShell.${system} = self.devShells.${system}.default; # compatibility
+
+      formatter.${system} = pkgs.nixfmt-tree;
     };
-    packages.${system} = {
-      inherit optionsDoc documentation;
-    };
-    devShells.${system}.default = pkgs.mkShellNoCC {
-      inputsFrom = [ documentation ];
-      packages = with pkgs; [
-        glab
-      ] ++ self.checks.${system}.pre-commit.enabledPackages;
-      shellHook = self.checks.${system}.pre-commit.shellHook;
-    };
-    devShell.${system} = self.devShells.${system}.default; # compatibility
-  };
 }

mail-server/assertions.nix

@@ -1,18 +1,146 @@
-{ config, lib, ... }:
 {
-  assertions = lib.optionals config.mailserver.ldap.enable [
-    {
-      assertion = config.mailserver.loginAccounts == {};
-      message = "When the LDAP support is enable (mailserver.ldap.enable = true), it is not possible to define mailserver.loginAccounts";
-    }
-    {
-      assertion = config.mailserver.extraVirtualAliases == {};
-      message = "When the LDAP support is enable (mailserver.ldap.enable = true), it is not possible to define mailserver.extraVirtualAliases";
-    }
-  ] ++ lib.optionals (config.mailserver.enable && config.mailserver.certificateScheme != "acme") [
-    {
-      assertion = config.mailserver.acmeCertificateName == config.mailserver.fqdn;
-      message = "When the certificate scheme is not 'acme' (mailserver.certificateScheme != \"acme\"), it is not possible to define mailserver.acmeCertificateName";
-    }
-  ];
+  config,
+  lib,
+  ...
+}:
+
+let
+  mailserverRelease = "26.05";
+  nixpkgsRelease = lib.trivial.release;
+  releaseMismatch =
+    config.mailserver.enableNixpkgsReleaseCheck && mailserverRelease != nixpkgsRelease;
+in
+
+{
+  warnings =
+    lib.optionals releaseMismatch [
+      ''
+        You are using
+
+          NixOS Mailserver version ${mailserverRelease} and
+          Nixpkgs version ${nixpkgsRelease}.
+
+        Using mismatched versions is likely to cause compatibility issues
+        and may require migrations that make an eventual rollback tricky.
+
+        It is therefore highly recommended to use a release of
+        NixOS mailserver that corresponds with your chosen release of Nixpkgs.
+
+        If you insist then you can disable this warning by adding
+
+          mailserver.enableNixpkgsReleaseCheck = false;
+
+        to your configuration.
+      ''
+    ]
+    ++ lib.optionals config.mailserver.borgbackup.enable [
+      ''
+        `mailserver.borgbackup` will be removed after 26.05.
+
+        The borgbackup integration will be removed with the recommendation to
+        migrate to the upstream `services.borgbackup` module, which receives far
+        superior maintenance and testing.
+
+        NixOS manual: https://nixos.org/manual/nixos/stable/#module-borgbase
+      ''
+    ]
+    ++ lib.optionals config.mailserver.backup.enable [
+      ''
+        `mailserver.backup` will be removed after 26.05.
+
+        The rsnapshot integration will be removed due to lack of maintenance,
+        expertise and tests to make sure it still works. Please use the upstream
+        module directly instead.
+      ''
+    ]
+    ++ lib.optionals config.mailserver.monitoring.enable [
+      ''
+        `mailserver.monitoring` will be removed after 26.05.
+
+        The monit integration will be removed due to lack of maintenance,
+        expertise and tests to make sure it still works.
+      ''
+    ];
+
+  # We guard all assertions by requiring mailserver to be actually enabled
+  assertions = lib.optionals config.mailserver.enable (
+    [
+      {
+        assertion = config.mailserver.stateVersion != null;
+        message = "The `mailserver.stateVersion` option is not set. Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html to determine the proper value to initialize it at.";
+      }
+      {
+        assertion =
+          config.mailserver.x509.useACMEHost != null
+          -> config.mailserver.x509.certificateFile == null && config.mailserver.x509.privateKeyFile == null;
+        message = "Configuring an ACME certificate (`mailserver.x509.useACMEHost`) is not possible while also passing an existing certificate (`mailserver.x509.certificateFile`, `mailserver.x509.privateKeyFile`).";
+      }
+      {
+        assertion =
+          config.mailserver.x509.useACMEHost != null
+          || (
+            config.mailserver.x509.certificateFile != null && config.mailserver.x509.privateKeyFile != null
+          );
+        message = "Configure either an ACME certificate (`mailserver.x509.useACMEHost`) or pass an existing certificate (`mailserver.x509.certificateFile`, `mailserver.x509.privateKeyFile`).";
+      }
+    ]
+    ++ lib.optionals config.mailserver.dkim.enable (
+      lib.flatten (
+        lib.mapAttrsToList (
+          domain: domainAttrs:
+          lib.mapAttrsToList (selector: selectorAttrs: [
+            {
+              assertion =
+                selectorAttrs.keyFile != null -> (selectorAttrs.keyType == null && selectorAttrs.keyLength == null);
+              message = "${domain} DKIM selector ${selector} can only use either `keyType`, `keyLength` OR `keyFile` not both.";
+            }
+          ]) domainAttrs.selectors
+        ) config.mailserver.dkim.domains
+      )
+    )
+    ++ lib.optionals (config.mailserver.ldap.enable && config.mailserver.storage.path != "/var/vmail") [
+      {
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 2;
+        message = ''
+          Issue: The dovecot homedir for LDAP users was previously not respecting `mailserver.storage.path`.
+          Remediation:
+            - Stop the `dovecot.service`
+            - Move `/var/vmail/ldap` below your `mailserver.storage.path`
+            - Increase the `stateVersion` to 2.
+
+          Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#dovecot-ldap-home-directory-migration for more information.
+        '';
+      }
+    ]
+    ++ [
+      {
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 3;
+        message = ''
+          Issue: The dovecot mail location for all users has changed and need to be migrated.
+
+          Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#dovecot-mail-directory-migration for the required remediation steps.
+        '';
+      }
+    ]
+    ++ lib.optionals (config.mailserver.ldap.enable) [
+      {
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 4;
+        message = ''
+          NixOS Mailserver requires migrating LDAP home directories to UUID scheme
+
+          Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#dovecot-ldap-uuid-based-home-directories for required migration steps.
+        '';
+      }
+    ]
+    ++ lib.optionals (config.mailserver.enableManageSieve) [
+      {
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 5;
+        message = ''
+          NixOS Mailserver requires moving the Sieve script directories into Dovecot home directories.
+
+          Check https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#sieve-script-directory-migration for required migration steps.
+        '';
+      }
+    ]
+  );
 }

mail-server/borgbackup.nix

@@ -14,28 +14,43 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
+{
+  config,
+  lib,
+  ...
+}:
 
 let
   cfg = config.mailserver.borgbackup;
 
   methodFragment = lib.optional (cfg.compression.method != null) cfg.compression.method;
   autoFragment =
-    if cfg.compression.auto && cfg.compression.method == null
-    then throw "compression.method must be set when using auto."
-    else lib.optional cfg.compression.auto "auto";
+    if cfg.compression.auto && cfg.compression.method == null then
+      throw "compression.method must be set when using auto."
+    else
+      lib.optional cfg.compression.auto "auto";
   levelFragment =
-    if cfg.compression.level != null && cfg.compression.method == null
-    then throw "compression.method must be set when using compression.level."
-    else lib.optional (cfg.compression.level != null) (toString cfg.compression.level);
-  compressionFragment = lib.concatStringsSep "," (lib.flatten [autoFragment methodFragment levelFragment]);
+    if cfg.compression.level != null && cfg.compression.method == null then
+      throw "compression.method must be set when using compression.level."
+    else
+      lib.optional (cfg.compression.level != null) (toString cfg.compression.level);
+  compressionFragment = lib.concatStringsSep "," (
+    lib.flatten [
+      autoFragment
+      methodFragment
+      levelFragment
+    ]
+  );
   compression = lib.optionalString (compressionFragment != "") "--compression ${compressionFragment}";
 
   encryptionFragment = cfg.encryption.method;
   passphraseFile = lib.escapeShellArg cfg.encryption.passphraseFile;
-  passphraseFragment = lib.optionalString (cfg.encryption.method != "none")
-                         (if cfg.encryption.passphraseFile != null then ''env BORG_PASSPHRASE="$(cat ${passphraseFile})"''
-                          else throw "passphraseFile must be set when using encryption.");
+  passphraseFragment = lib.optionalString (cfg.encryption.method != "none") (
+    if cfg.encryption.passphraseFile != null then
+      ''env BORG_PASSPHRASE="$(cat ${passphraseFile})"''
+    else
+      throw "passphraseFile must be set when using encryption."
+  );
 
   locations = lib.escapeShellArgs cfg.locations;
   name = lib.escapeShellArg cfg.name;
@@ -51,14 +66,15 @@ let
   borgScript = ''
     export BORG_REPO=${repoLocation}
     ${cmdPreexec}
-    ${passphraseFragment} ${pkgs.borgbackup}/bin/borg init ${extraInitArgs} --encryption ${encryptionFragment} || true
-    ${passphraseFragment} ${pkgs.borgbackup}/bin/borg create ${extraCreateArgs} ${compression} ::${name} ${locations}
+    ${passphraseFragment} ${lib.getExe' config.services.borgbackup.package "borg"} init ${extraInitArgs} --encryption ${encryptionFragment} || true
+    ${passphraseFragment} ${lib.getExe' config.services.borgbackup.package "borg"} create ${extraCreateArgs} ${compression} ::${name} ${locations}
     ${cmdPostexec}
   '';
-in {
+in
+{
   config = lib.mkIf (config.mailserver.enable && cfg.enable) {
-    environment.systemPackages = with pkgs; [
-      borgbackup
+    environment.systemPackages = [
+      config.services.borgbackup.package
     ];
 
     systemd.services.borgbackup = {

mail-server/common.nix

@@ -14,57 +14,78 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib }:
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
 
 let
   cfg = config.mailserver;
 in
-{
-  # cert :: PATH
-  certificatePath = if cfg.certificateScheme == "manual"
-             then cfg.certificateFile
-             else if cfg.certificateScheme == "selfsigned"
-                  then "${cfg.certificateDirectory}/cert-${cfg.fqdn}.pem"
-                  else if cfg.certificateScheme == "acme" || cfg.certificateScheme == "acme-nginx"
-                       then "${config.security.acme.certs.${cfg.acmeCertificateName}.directory}/fullchain.pem"
-                       else throw "unknown certificate scheme";
+rec {
+  withACME = cfg.x509.useACMEHost != null;
 
-  # key :: PATH
-  keyPath = if cfg.certificateScheme == "manual"
-        then cfg.keyFile
-        else if cfg.certificateScheme == "selfsigned"
-             then "${cfg.certificateDirectory}/key-${cfg.fqdn}.pem"
-              else if cfg.certificateScheme == "acme" || cfg.certificateScheme == "acme-nginx"
-                   then "${config.security.acme.certs.${cfg.acmeCertificateName}.directory}/key.pem"
-                   else throw "unknown certificate scheme";
+  x509CertificateFile =
+    if withACME then
+      "${config.security.acme.certs.${cfg.x509.useACMEHost}.directory}/fullchain.pem"
+    else
+      cfg.x509.certificateFile;
 
-  passwordFiles = let
-    mkHashFile = name: hash: pkgs.writeText "${builtins.hashString "sha256" name}-password-hash" hash;
-  in
-    lib.mapAttrs (name: value:
-    if value.hashedPasswordFile == null then
-      builtins.toString (mkHashFile name value.hashedPassword)
-    else value.hashedPasswordFile) cfg.loginAccounts;
+  x509PrivateKeyFile =
+    if withACME then
+      "${config.security.acme.certs.${cfg.x509.useACMEHost}.directory}/key.pem"
+    else
+      cfg.x509.privateKeyFile;
+
+  passwordFiles =
+    let
+      mkHashFile = name: hash: pkgs.writeText "${builtins.hashString "sha256" name}-password-hash" hash;
+    in
+    lib.mapAttrs (
+      name: value:
+      if value.hashedPasswordFile != null then
+        value.hashedPasswordFile
+      else if value.hashedPassword != null then
+        builtins.toString (mkHashFile name value.hashedPassword)
+      else
+        value.passwordFile
+    ) cfg.accounts;
+
+  # Collect accounts with plain text passwords that require hashing
+  accountsWithPlaintextPasswordFiles = lib.filter (name: cfg.accounts.${name}.passwordFile != null) (
+    builtins.attrNames cfg.accounts
+  );
 
   # Appends the LDAP bind password to files to avoid writing this
   # password into the Nix store.
-  appendLdapBindPwd = {
-    name, file, prefix, suffix ? "", passwordFile, destination
-  }: pkgs.writeScript "append-ldap-bind-pwd-in-${name}" ''
-    #!${pkgs.stdenv.shell}
-    set -euo pipefail
+  appendLdapBindPwd =
+    {
+      name,
+      file,
+      prefix,
+      suffix ? "",
+      passwordFile,
+      destination,
+    }:
+    pkgs.writeScript "append-ldap-bind-pwd-in-${name}"
+      # bash
+      ''
+        #!${pkgs.stdenv.shell}
+        set -euo pipefail
 
-    baseDir=$(dirname ${destination})
-    if (! test -d "$baseDir"); then
-      mkdir -p $baseDir
-      chmod 755 $baseDir
-    fi
+        baseDir=$(dirname ${destination})
+        if (! test -d "$baseDir"); then
+          mkdir -p $baseDir
+          chmod 755 $baseDir
+        fi
 
-    cat ${file} > ${destination}
-    echo -n '${prefix}' >> ${destination}
-    cat ${passwordFile} | tr -d '\n' >> ${destination}
-    echo -n '${suffix}' >> ${destination}
-    chmod 600 ${destination}
-  '';
+        cat ${file} > ${destination}
+        echo -n '${prefix}' >> ${destination}
+        cat ${passwordFile} | tr -d '\n' >> ${destination}
+        echo -n '${suffix}' >> ${destination}
+        chmod 600 ${destination}
+      '';
 
 }

mail-server/default.nix

@@ -0,0 +1,17 @@
+{
+  imports = [
+    ./assertions.nix
+    ./borgbackup.nix
+    ./rsnapshot.nix
+    ./clamav.nix
+    ./monit.nix
+    ./users.nix
+    ./environment.nix
+    ./networking.nix
+    ./systemd.nix
+    ./dovecot.nix
+    ./postfix.nix
+    ./rspamd.nix
+    ./kresd.nix
+  ];
+}

mail-server/dovecot.nix

@@ -14,388 +14,539 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ options, config, pkgs, lib, ... }:
+{
+  config,
+  options,
+  pkgs,
+  lib,
+  ...
+}:
 
-with (import ./common.nix { inherit config pkgs lib; });
+with (import ./common.nix {
+  inherit
+    config
+    options
+    pkgs
+    lib
+    ;
+});
 
 let
+  inherit (lib)
+    attrNames
+    concatMapStringsSep
+    filterAttrs
+    mapAttrs'
+    mkForce
+    mkIf
+    mkMerge
+    nameValuePair
+    ;
+
   cfg = config.mailserver;
 
   passwdDir = "/run/dovecot2";
   passwdFile = "${passwdDir}/passwd";
   userdbFile = "${passwdDir}/userdb";
-  # This file contains the ldap bind password
-  ldapConfFile = "${passwdDir}/dovecot-ldap.conf.ext";
-  boolToYesNo = x: if x then "yes" else "no";
-  listToLine = lib.concatStringsSep " ";
-  listToMultiAttrs = keyPrefix: attrs: lib.listToAttrs (lib.imap1 (n: x: {
-    name = "${keyPrefix}${if n==1 then "" else toString n}";
-    value = x;
-  }) attrs);
 
-  maildirLayoutAppendix = lib.optionalString cfg.useFsLayout ":LAYOUT=fs";
-  maildirUTF8FolderNames = lib.optionalString cfg.useUTF8FolderNames ":UTF-8";
+  genPasswdScript =
+    pkgs.writeScript "generate-password-file"
+      # bash
+      ''
+        #!${pkgs.stdenv.shell}
 
-  # maildir in format "/${domain}/${user}"
-  dovecotMaildir =
-    "maildir:${cfg.mailDirectory}/%{domain}/%{username}${maildirLayoutAppendix}${maildirUTF8FolderNames}"
-    + (lib.optionalString (cfg.indexDir != null)
-       ":INDEX=${cfg.indexDir}/%{domain}/%{username}"
-      );
+        set -euo pipefail
 
-  postfixCfg = config.services.postfix;
+        if (! test -d "${passwdDir}"); then
+          mkdir "${passwdDir}"
+          chmod 755 "${passwdDir}"
+        fi
 
-  ldapConfig = pkgs.writeTextFile {
-    name = "dovecot-ldap.conf.ext.template";
-    text = ''
-      ldap_version = 3
-      uris = ${lib.concatStringsSep " " cfg.ldap.uris}
-      ${lib.optionalString cfg.ldap.startTls ''
-      tls = yes
-      ''}
-      tls_require_cert = hard
-      tls_ca_cert_file = ${cfg.ldap.tlsCAFile}
-      dn = ${cfg.ldap.bind.dn}
-      sasl_bind = no
-      auth_bind = yes
-      base = ${cfg.ldap.searchBase}
-      scope = ${mkLdapSearchScope cfg.ldap.searchScope}
-      ${lib.optionalString (cfg.ldap.dovecot.userAttrs != null) ''
-      user_attrs = ${cfg.ldap.dovecot.userAttrs}
-      ''}
-      user_filter = ${cfg.ldap.dovecot.userFilter}
-      ${lib.optionalString (cfg.ldap.dovecot.passAttrs != "") ''
-      pass_attrs = ${cfg.ldap.dovecot.passAttrs}
-      ''}
-      pass_filter = ${cfg.ldap.dovecot.passFilter}
-    '';
-  };
+        # Prevent world-readable password files, even temporarily.
+        umask 077
 
-  setPwdInLdapConfFile = appendLdapBindPwd {
-    name = "ldap-conf-file";
-    file = ldapConfig;
-    prefix = ''dnpass = "'';
-    suffix = ''"'';
-    passwordFile = cfg.ldap.bind.passwordFile;
-    destination = ldapConfFile;
-  };
+        prepend_scheme() {
+          case "$1" in
+            {*}*) printf '%s' "$1" ;;
+            *) printf '{CRYPT}%s' "$1" ;;
+          esac
+        }
 
-  genPasswdScript = pkgs.writeScript "generate-password-file" ''
-    #!${pkgs.stdenv.shell}
+        for f in ${
+          builtins.toString (lib.mapAttrsToList (name: _: passwordFiles."${name}") cfg.accounts)
+        }; do
+          if [ ! -f "$f" ]; then
+            echo "Expected password hash file $f does not exist!"
+            exit 1
+          fi
+        done
 
-    set -euo pipefail
+        cat <<EOF > ${passwdFile}
+        ${lib.concatStringsSep "\n" (
+          lib.mapAttrsToList (
+            name: _:
+            if lib.elem name accountsWithPlaintextPasswordFiles then
+              "${name}:${"$(sed -n '1{p;p;q}' ${passwordFiles."${name}"} | ${lib.getExe' config.services.dovecot2.package "doveadm"} pw)"}::::::"
+            else
+              "${name}:${"$(prepend_scheme \"$(head -n 1 ${passwordFiles."${name}"})\")"}::::::"
+          ) cfg.accounts
+        )}
+        EOF
+        chown dovecot2:dovecot2 ${passwdFile}
 
-    if (! test -d "${passwdDir}"); then
-      mkdir "${passwdDir}"
-      chmod 755 "${passwdDir}"
-    fi
+        cat <<EOF > ${userdbFile}
+        ${lib.concatStringsSep "\n" (
+          lib.mapAttrsToList (
+            name: value:
+            # https://doc.dovecot.org/2.4.3/core/config/auth/databases/passwd_file.html
+            # https://doc.dovecot.org/2.4.3/core/plugins/quota.html#per-user-quota
+            # https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/67DBLLW4L5QBTEYRKGA26POFZ52ZR7ZO/#67DBLLW4L5QBTEYRKGA26POFZ52ZR7ZO
+            "${name}:::::::"
+            + lib.optionalString (value.quota != null) "userdb_quota/user/storage_size=${value.quota}"
+          ) cfg.accounts
+        )}
+        EOF
+        chown dovecot2:dovecot2 ${userdbFile}
+      '';
 
-    # Prevent world-readable password files, even temporarily.
-    umask 077
-
-    for f in ${builtins.toString (lib.mapAttrsToList (name: _: passwordFiles."${name}") cfg.loginAccounts)}; do
-      if [ ! -f "$f" ]; then
-        echo "Expected password hash file $f does not exist!"
-        exit 1
-      fi
-    done
-
-    cat <<EOF > ${passwdFile}
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: _:
-      "${name}:${"$(head -n 1 ${passwordFiles."${name}"})"}::::::"
-    ) cfg.loginAccounts)}
-    EOF
-
-    cat <<EOF > ${userdbFile}
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value:
-      "${name}:::::::"
-        + lib.optionalString (value.quota != null) "userdb_quota_rule=*:storage=${value.quota}"
-    ) cfg.loginAccounts)}
-    EOF
-  '';
-
-  junkMailboxes = builtins.attrNames (lib.filterAttrs (_: v: v ? "specialUse" && v.specialUse == "Junk") cfg.mailboxes);
+  junkMailboxes = builtins.attrNames (
+    lib.filterAttrs (_: v: v ? "special_use" && v.special_use == "\\Junk") cfg.mailboxes
+  );
   junkMailboxNumber = builtins.length junkMailboxes;
-  # The assertion garantees there is exactly one Junk mailbox.
+  # The assertion guarantees there is exactly one Junk mailbox.
   junkMailboxName = if junkMailboxNumber == 1 then builtins.elemAt junkMailboxes 0 else "";
 
-  mkLdapSearchScope = scope: (
-    if scope == "sub" then "subtree"
-    else if scope == "one" then "onelevel"
-    else scope
-  );
-
-  dovecotModules = [
-    pkgs.dovecot_pigeonhole
-  ] ++ lib.optional cfg.fullTextSearch.enable pkgs.dovecot-fts-flatcurve;
-  # Remove and assume `false` after NixOS 25.05
-  haveDovecotModulesOption = options.services.dovecot2 ? "modules" && (options.services.dovecot2.modules.visible or true);
-
-  ftsPluginSettings = {
-    fts = "flatcurve";
-    fts_languages = listToLine cfg.fullTextSearch.languages;
-    fts_tokenizers = listToLine [ "generic" "email-address" ];
-    fts_tokenizer_email_address = "maxlen=100"; # default 254 too large for Xapian
-    fts_flatcurve_substring_search = boolToYesNo cfg.fullTextSearch.substringSearch;
-    fts_filters = listToLine cfg.fullTextSearch.filters;
-    fts_header_excludes = listToLine cfg.fullTextSearch.headerExcludes;
-    fts_autoindex = boolToYesNo cfg.fullTextSearch.autoIndex;
-    fts_enforced = cfg.fullTextSearch.enforced;
-  } // (listToMultiAttrs "fts_autoindex_exclude" cfg.fullTextSearch.autoIndexExclude);
-
+  mkLdapSearchScope =
+    scope:
+    (
+      if scope == "sub" then
+        "subtree"
+      else if scope == "one" then
+        "onelevel"
+      else
+        scope
+    );
 in
 {
-  config = with cfg; lib.mkIf enable {
+  config = lib.mkIf cfg.enable {
     assertions = [
       {
         assertion = junkMailboxNumber == 1;
-        message = "nixos-mailserver requires exactly one dovecot mailbox with the 'special use' flag set to 'Junk' (${builtins.toString junkMailboxNumber} have been found)";
+        message = "nixos-mailserver requires exactly one dovecot mailbox with the 'special_use' flag set to '\\Junk' (${builtins.toString junkMailboxNumber} have been found)";
       }
+      (
+        let
+          usersWithQuota = attrNames (
+            filterAttrs (_: account: account.quota != null) config.mailserver.accounts
+          );
+        in
+        {
+          assertion = !cfg.quota.enable -> usersWithQuota == [ ];
+          message = ''
+            Without quota support enabled, per-user quotas cannot be applied to the following accounts:
+
+              ${concatMapStringsSep "\n" (account: "- ${account}") usersWithQuota}
+
+              Either remove per user quota settings or re-enable `mailserver.quota.enable`.
+          '';
+        }
+      )
     ];
 
     warnings =
-      (lib.optional (
-        (builtins.length cfg.fullTextSearch.languages > 1) &&
-        (builtins.elem "stopwords" cfg.fullTextSearch.filters)
-      ) ''
-        Using stopwords in `mailserver.fullTextSearch.filters` with multiple
-        languages in `mailserver.fullTextSearch.languages` configured WILL
-        cause some searches to fail.
+      lib.optional
+        (
+          (builtins.length cfg.fullTextSearch.languages > 1)
+          && (builtins.elem "stopwords" cfg.fullTextSearch.filters)
+        )
+        ''
+          Using stopwords in `mailserver.fullTextSearch.filters` with multiple
+          languages in `mailserver.fullTextSearch.languages` configured WILL
+          cause some searches to fail.
 
-        The recommended solution is to NOT use the stopword filter when
-        multiple languages are present in the configuration.
-      '')
-    ;
-
-    # for sieve-test. Shelling it in on demand usually doesnt' work, as it reads
-    # the global config and tries to open shared libraries configured in there,
-    # which are usually not compatible.
-    environment.systemPackages = [
-      pkgs.dovecot_pigeonhole
-    ] ++ lib.optionals (!haveDovecotModulesOption) dovecotModules;
-
-    # For compatibility with python imaplib
-    environment.etc = lib.mkIf (!haveDovecotModulesOption) {
-      "dovecot/modules".source = "/run/current-system/sw/lib/dovecot/modules";
-    };
-
-    services.dovecot2 = lib.mkMerge [{
-      enable = true;
-      enableImap = enableImap || enableImapSsl;
-      enablePop3 = enablePop3 || enablePop3Ssl;
-      enablePAM = false;
-      enableQuota = true;
-      mailGroup = vmailGroupName;
-      mailUser = vmailUserName;
-      mailLocation = dovecotMaildir;
-      sslServerCert = certificatePath;
-      sslServerKey = keyPath;
-      enableLmtp = true;
-      mailPlugins.globally.enable = lib.optionals cfg.fullTextSearch.enable [
-        "fts"
-        "fts_flatcurve"
-      ];
-      protocols = lib.optional cfg.enableManageSieve "sieve";
-
-      pluginSettings = {
-        sieve = "file:${cfg.sieveDirectory}/%{user}/scripts;active=${cfg.sieveDirectory}/%{user}/active.sieve";
-        sieve_default = "file:${cfg.sieveDirectory}/%{user}/default.sieve";
-        sieve_default_name = "default";
-      } // (lib.optionalAttrs cfg.fullTextSearch.enable ftsPluginSettings);
-
-      sieve = {
-        extensions = [
-          "fileinto"
-        ];
-
-        scripts.after = builtins.toFile "spam.sieve" ''
-          require "fileinto";
-
-          if header :is "X-Spam" "Yes" {
-              fileinto "${junkMailboxName}";
-              stop;
-          }
+          The recommended solution is to NOT use the stopword filter when
+          multiple languages are present in the configuration.
         '';
 
-        pipeBins = map lib.getExe [
-          (pkgs.writeShellScriptBin "rspamd-learn-ham.sh"
-            "exec ${pkgs.rspamd}/bin/rspamc -h /run/rspamd/worker-controller.sock learn_ham")
-          (pkgs.writeShellScriptBin "rspamd-learn-spam.sh"
-            "exec ${pkgs.rspamd}/bin/rspamc -h /run/rspamd/worker-controller.sock learn_spam")
-        ];
+    security.acme.certs = lib.mkIf withACME {
+      ${cfg.x509.useACMEHost} = {
+        reloadServices = [ "dovecot.service" ];
       };
-
-      imapsieve.mailbox = [
-        {
-          name = junkMailboxName;
-          causes = [ "COPY" "APPEND" ];
-          before = ./dovecot/imap_sieve/report-spam.sieve;
-        }
-        {
-          name = "*";
-          from = junkMailboxName;
-          causes = [ "COPY" ];
-          before = ./dovecot/imap_sieve/report-ham.sieve;
-        }
-      ];
-
-      mailboxes = cfg.mailboxes;
-
-      extraConfig = ''
-        #Extra Config
-        ${lib.optionalString debug ''
-          mail_debug = yes
-          auth_debug = yes
-          verbose_ssl = yes
-        ''}
-
-        ${lib.optionalString (cfg.enableImap || cfg.enableImapSsl) ''
-          service imap-login {
-            inet_listener imap {
-              ${if cfg.enableImap then ''
-                port = 143
-              '' else ''
-                # see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
-                port = 0
-              ''}
-            }
-            inet_listener imaps {
-              ${if cfg.enableImapSsl then ''
-                port = 993
-                ssl = yes
-              '' else ''
-                # see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
-                port = 0
-              ''}
-            }
-          }
-        ''}
-        ${lib.optionalString (cfg.enablePop3 || cfg.enablePop3Ssl) ''
-          service pop3-login {
-            inet_listener pop3 {
-              ${if cfg.enablePop3 then ''
-                port = 110
-              '' else ''
-                # see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
-                port = 0
-              ''}
-            }
-            inet_listener pop3s {
-              ${if cfg.enablePop3Ssl then ''
-                port = 995
-                ssl = yes
-              '' else ''
-                # see https://dovecot.org/pipermail/dovecot/2010-March/047479.html
-                port = 0
-              ''}
-            }
-          }
-        ''}
-
-        protocol imap {
-          mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
-          mail_plugins = $mail_plugins imap_sieve
-        }
-
-        service imap {
-          vsz_limit = ${builtins.toString cfg.imapMemoryLimit} MB
-        }
-
-        protocol pop3 {
-          mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
-        }
-
-        mail_access_groups = ${vmailGroupName}
-        ssl = required
-        ssl_min_protocol = TLSv1.2
-        ssl_prefer_server_ciphers = no
-
-        service lmtp {
-          unix_listener dovecot-lmtp {
-            group = ${postfixCfg.group}
-            mode = 0600
-            user = ${postfixCfg.user}
-          }
-          vsz_limit = ${builtins.toString cfg.lmtpMemoryLimit} MB
-        }
-
-        service quota-status {
-          inet_listener {
-            port = 0
-          }
-          unix_listener quota-status {
-            user = postfix
-          }
-          vsz_limit = ${builtins.toString cfg.quotaStatusMemoryLimit} MB
-        }
-
-        recipient_delimiter = ${cfg.recipientDelimiter}
-        lmtp_save_to_detail_mailbox = ${cfg.lmtpSaveToDetailMailbox}
-
-        protocol lmtp {
-          mail_plugins = $mail_plugins sieve
-        }
-
-        passdb {
-          driver = passwd-file
-          args = ${passwdFile}
-        }
-
-        userdb {
-          driver = passwd-file
-          args = ${userdbFile}
-          default_fields = uid=${builtins.toString cfg.vmailUID} gid=${builtins.toString cfg.vmailUID} home=${cfg.mailDirectory}
-        }
-
-        ${lib.optionalString cfg.ldap.enable ''
-        passdb {
-          driver = ldap
-          args = ${ldapConfFile}
-        }
-
-        userdb {
-          driver = ldap
-          args = ${ldapConfFile}
-          default_fields = home=/var/vmail/ldap/%{user} uid=${toString cfg.vmailUID} gid=${toString cfg.vmailUID}
-        }
-        ''}
-
-        service auth {
-          unix_listener auth {
-            mode = 0660
-            user = ${postfixCfg.user}
-            group = ${postfixCfg.group}
-          }
-        }
-
-        auth_mechanisms = plain login
-
-        namespace inbox {
-          separator = ${cfg.hierarchySeparator}
-          inbox = yes
-        }
-
-        service indexer-worker {
-        ${lib.optionalString (cfg.fullTextSearch.memoryLimit != null) ''
-          vsz_limit = ${toString (cfg.fullTextSearch.memoryLimit*1024*1024)}
-        ''}
-        }
-
-        lda_mailbox_autosubscribe = yes
-        lda_mailbox_autocreate = yes
-      '';
-    }
-      (lib.mkIf haveDovecotModulesOption {
-        modules = dovecotModules;
-      })
-    ];
-
-    systemd.services.dovecot2 = {
-      preStart = ''
-        ${genPasswdScript}
-      '' + (lib.optionalString cfg.ldap.enable setPwdInLdapConfFile);
     };
 
-    systemd.services.postfix.restartTriggers = [ genPasswdScript ] ++ (lib.optional cfg.ldap.enable [setPwdInLdapConfFile]);
+    # Dovecot modules
+    environment.systemPackages = [
+      pkgs.dovecot_pigeonhole
+    ];
+
+    # For compatibility with python imaplib
+    environment.etc."dovecot/modules".source = "/run/current-system/sw/lib/dovecot/modules";
+
+    services.dovecot2 = {
+      enable = true;
+      package = pkgs.dovecot; # pin over stateVersion logic in nixox 26.05
+      enablePAM = mkForce false;
+
+      sieve.pipeBins = map lib.getExe [
+        (pkgs.writeShellScriptBin "rspamd-learn-ham.sh" "exec ${lib.getExe' config.services.rspamd.package "rspamc"} -h /run/rspamd/worker-controller.sock learn_ham")
+        (pkgs.writeShellScriptBin "rspamd-learn-spam.sh" "exec ${lib.getExe' config.services.rspamd.package "rspamc"} -h /run/rspamd/worker-controller.sock learn_spam")
+      ];
+
+      # https://doc.dovecot.org/2.4.3/core/settings/syntax.html
+      # https://doc.dovecot.org/2.4.3/core/settings/types.html#boolean-list
+      settings = mkMerge [
+        ({
+          # https://doc.dovecot.org/main/core/summaries/settings.html#dovecot_config_version
+          dovecot_config_version = "2.4.3";
+          # https://doc.dovecot.org/main/core/summaries/settings.html#dovecot_storage_version
+          dovecot_storage_version = "2.3.21.1";
+
+          # server identity
+          hostname = cfg.fqdn;
+
+          # vmail user
+          mail_uid = cfg.storage.owner;
+          mail_gid = cfg.storage.group;
+          mail_access_groups = cfg.storage.group;
+
+          # authentication
+          auth_mechanisms = [
+            "plain"
+            "login"
+          ];
+
+          # backend services
+          "service anvil" = {
+            "unix_listener anvil" = {
+              mode = "0660";
+              group = cfg.storage.group;
+            };
+          };
+          "service auth" = {
+            "unix_listener auth" = {
+              user = config.services.postfix.user;
+              group = config.services.postfix.group;
+              mode = "0660";
+            };
+          };
+          "service lmtp" = {
+            "unix_listener dovecot-lmtp" = {
+              user = config.services.postfix.user;
+              group = config.services.postfix.group;
+              mode = "0600";
+            };
+            user = cfg.storage.owner;
+            vsz_limit = "${toString cfg.lmtpMemoryLimit} MB";
+          };
+
+          # frontend services
+          "service imap-login" = mkIf (cfg.enableImap || cfg.enableImapSsl) {
+            "inet_listener imap" = {
+              # https://dovecot.org/pipermail/dovecot/2010-March/047479.html
+              port = if cfg.enableImap then 143 else 0;
+            };
+            "inet_listener imaps" = mkIf cfg.enableImapSsl {
+              port = 993;
+              ssl = true;
+            };
+          };
+          "service pop3-login" = mkIf (cfg.enablePop3 || cfg.enablePop3Ssl) {
+            "inet_listener pop3" = {
+              # https://dovecot.org/pipermail/dovecot/2010-March/047479.html
+              port = if cfg.enablePop3 then 110 else 0;
+            };
+            "inet_listener pop3s" = mkIf cfg.enablePop3Ssl {
+              port = 995;
+              ssl = true;
+            };
+          };
+          "service imap" = {
+            vsz_limit = "${toString cfg.imapMemoryLimit} MB";
+          };
+
+          # protocols
+          protocols = {
+            lmtp = true;
+            imap = cfg.enableImap || cfg.enableImapSsl;
+            pop3 = cfg.enablePop3 || cfg.enablePop3Ssl;
+            sieve = cfg.enableManageSieve;
+          };
+
+          "protocol lmtp" = {
+            mail_plugins = {
+              sieve = true;
+            };
+          };
+          "protocol imap" = {
+            mail_max_userip_connections = cfg.maxConnectionsPerUser;
+            mail_plugins = {
+              imap_sieve = true;
+            };
+          };
+          "protocol pop3" = {
+            mail_max_userip_connections = cfg.maxConnectionsPerUser;
+          };
+
+          # tls settings
+          ssl_server_cert_file = x509CertificateFile;
+          ssl_server_key_file = x509PrivateKeyFile;
+          # https://ssl-config.mozilla.org/#server=dovecot&version=2.3.21&config=intermediate&openssl=3.4.1&guideline=5.7
+          ssl = "required";
+          ssl_min_protocol = "TLSv1";
+          ssl_server_prefer_ciphers = "client";
+          ssl_cipher_list = lib.concatStringsSep ":" [
+            # TLS1.3
+            "TLS_AES_128_GCM_SHA256"
+            "TLS_CHACHA20_POLY1305_SHA256"
+            "TLS_AES_256_GCM_SHA384"
+            # TLS1.2
+            # EC key material
+            "ECDHE-ECDSA-AES128-GCM-SHA256"
+            "ECDHE-ECDSA-CHACHA20-POLY1305"
+            "ECDHE-ECDSA-AES256-GCM-SHA384"
+            # RSA key material
+            "ECDHE-RSA-AES128-GCM-SHA256"
+            "ECDHE-RSA-CHACHA20-POLY1305"
+            "ECDHE-RSA-AES256-GCM-SHA384"
+          ];
+          ssl_curve_list = lib.concatStringsSep ":" [
+            "X25519MLKEM768"
+            "X25519"
+            "SecP256r1MLKEM768"
+            "prime256v1"
+            "secp384r1"
+          ];
+
+          # default user mailboxes
+          "namespace inbox" = {
+            inbox = true;
+            separator = cfg.hierarchySeparator;
+          }
+          // mapAttrs' (name: value: nameValuePair ''mailbox "${name}"'' value) cfg.mailboxes;
+          lda_mailbox_autosubscribe = true;
+          lda_mailbox_autocreate = true;
+
+          # subaddressing
+          recipient_delimiter = cfg.recipientDelimiter;
+          lmtp_save_to_detail_mailbox = cfg.lmtpSaveToDetailMailbox;
+
+          # sieve filtering
+          "sieve_script spamfilter" = {
+            # junk filter
+            path = pkgs.writeText "after.sieve" ''
+              require "fileinto";
+
+              if header :is "X-Spam" "Yes" {
+                  fileinto "${junkMailboxName}";
+                  stop;
+              }
+            '';
+            type = "after";
+          };
+          "sieve_script default" = {
+            # declarative
+            type = "default";
+            name = "default";
+            # TODO: Pre-compile Sieve scripts with 'sievec' (requires a Dovecot config in build sandbox)
+            path = "${
+              pkgs.runCommand "declarative-sieve-scripts" { } (
+                ''
+                  mkdir "$out"
+                ''
+                + lib.concatMapAttrsStringSep "\n" (_: value: ''
+                  mkdir "$out/${value.name}"
+                  cp -v "${builtins.toFile "default.sieve" value.sieveScript}" "$out/${value.name}/default.sieve"
+                '') (lib.filterAttrs (_: value: value.sieveScript != null) cfg.accounts)
+              )
+            }/%{user}/default.sieve";
+          };
+
+          "sieve_script personal" = {
+            # managesieve
+            type = "personal";
+            # Upstream default, but we want to be explicit about it
+            # https://doc.dovecot.org/main/core/plugins/sieve.html#script-storage-type-personal
+            active_path = "~/.dovecot.sieve";
+            path = "~/sieve";
+          };
+
+          sieve_extensions = {
+            fileinto = true;
+          };
+          sieve_global_extensions = {
+            "vnd.dovecot.pipe" = true;
+          };
+          sieve_plugins = {
+            sieve_imapsieve = true;
+            sieve_extprograms = true;
+          };
+
+          # imapsieve (spam/ham learning)
+          "mailbox ${junkMailboxName}" = {
+            "sieve_script spam" = {
+              cause = [
+                "APPEND"
+                "COPY"
+              ];
+              path = ./dovecot/imap_sieve/report-spam.sieve;
+              type = "before";
+            };
+          };
+          "imapsieve_from ${junkMailboxName}" = {
+            "sieve_script ham" = {
+              cause = "copy";
+              path = ./dovecot/imap_sieve/report-ham.sieve;
+              type = "before";
+            };
+          };
+
+          mailbox_list_layout = cfg.storage.directoryLayout;
+          mailbox_list_utf8 = cfg.useUTF8FolderNames;
+          mail_driver = "maildir";
+          mail_path = "~/mail";
+
+          # declarative users
+          "userdb declarative" = {
+            driver = "passwd-file";
+            passwd_file_path = userdbFile;
+            fields = {
+              home = "${cfg.storage.path}/%{user | domain}/%{user | username}";
+              inherit (cfg.storage) uid gid;
+              mail_index_path = mkIf (cfg.indexDir != null) "${cfg.indexDir}/%{user | domain}/%{user | username}";
+            };
+          };
+          "passdb declarative" = {
+            driver = "passwd-file";
+            passwd_file_path = passwdFile;
+          };
+
+        })
+        (mkIf cfg.ldap.enable {
+          # ldap users
+          ssl_client_ca_file = cfg.ldap.caFile;
+          ssl_client_require_valid_cert = true;
+
+          ldap_version = 3;
+          ldap_uris = cfg.ldap.uris;
+          ldap_starttls = cfg.ldap.startTls;
+          ldap_auth_dn = cfg.ldap.bind.dn;
+          ldap_auth_dn_password = "</run/credentials/dovecot.service/ldap-bind-pw";
+          ldap_base = cfg.ldap.base;
+          ldap_scope = mkLdapSearchScope cfg.ldap.scope;
+
+          "userdb ldap" = {
+            driver = "ldap";
+            filter = cfg.ldap.dovecot.userFilter;
+            fields = {
+              home = "${cfg.storage.path}/ldap/%{ldap:${cfg.ldap.attributes.uuid}}";
+              inherit (cfg.storage) uid gid;
+              mail_index_path = mkIf (
+                cfg.indexDir != null
+              ) "${cfg.indexDir}/ldap/%{ldap:${cfg.ldap.attributes.uuid}}";
+            };
+            ldap_connection_group = "ldap-userdb-conn";
+          };
+          "passdb ldap" = {
+            driver = "ldap";
+            filter = cfg.ldap.dovecot.passFilter;
+            bind = cfg.ldap.attributes.password == null;
+            fields = {
+              password = mkIf (cfg.ldap.attributes.password != null) "%{ldap:${cfg.ldap.attributes.password}}";
+            };
+            ldap_connection_group = "ldap-passdb-conn";
+          };
+        })
+        (mkIf cfg.quota.enable {
+          mail_plugins.quota = true;
+
+          "protocol imap".mail_plugins.imap_quota = true;
+
+          "service quota-status" = {
+            executable = toString [
+              "${config.services.dovecot2.package}/libexec/dovecot/quota-status"
+              "-p"
+              "postfix"
+            ];
+            "unix_listener quota-status" = {
+              user = "postfix";
+            };
+            client_limit = 1;
+            vsz_limit = "${toString cfg.quotaStatusMemoryLimit} MB";
+          };
+
+          quota_status_success = "DUNNO";
+          quota_status_nouser = "DUNNO";
+          quota_status_overquota = "552 5.2.2 Mailbox is full";
+          # quota_storage_grace = "10M";
+
+          "quota user" = {
+            driver = "count";
+            storage_size = mkIf (cfg.quota.defaults.perUser != null) cfg.quota.defaults.perUser;
+          };
+        })
+        (mkIf cfg.fullTextSearch.enable (
+          {
+            mail_plugins = {
+              fts = true;
+              fts_flatcurve = true;
+            };
+
+            "service indexer-worker" = mkIf (cfg.fullTextSearch.memoryLimit != null) {
+              vsz_limit = "${toString cfg.fullTextSearch.memoryLimit} MB";
+            };
+
+            fts_autoindex = cfg.fullTextSearch.autoIndex;
+            fts_driver = "flatcurve";
+            fts_search_add_missing = "yes";
+            fts_search_read_fallback = cfg.fullTextSearch.fallback;
+            fts_header_excludes = lib.genAttrs cfg.fullTextSearch.headerExcludes (_: true);
+
+            "fts flatcurve" = {
+              flatcurve_substring_search = cfg.fullTextSearch.substringSearch;
+            };
+
+            # languages
+            language_filters = lib.genAttrs cfg.fullTextSearch.filters (_: true);
+            language_tokenizer_address_token_maxlen = 100; # default 250 too large for Xapian
+          }
+          # build languages from list, the first one becomes the default language
+          // lib.listToAttrs (
+            lib.imap0 (i: lang: {
+              name = "language ${lang}";
+              value = (if i == 0 then { default = true; } else { }) // {
+                language_tokenizers = [
+                  "generic"
+                  "email-address"
+                ];
+              };
+            }) cfg.fullTextSearch.languages
+          )
+        ))
+        (mkIf cfg.debug.dovecot {
+          mail_debug = true;
+          # https://doc.dovecot.org/2.4.3/core/config/events/filter.html#common-unified-filter-language
+          log_debug = "category=ssl OR category=auth";
+        })
+      ];
+    };
+
+    systemd.services.dovecot = {
+      preStart = ''
+        ${genPasswdScript}
+      '';
+      reloadTriggers = lib.mkIf (!withACME) [
+        x509CertificateFile
+        x509PrivateKeyFile
+      ];
+      serviceConfig = lib.optionalAttrs cfg.ldap.enable {
+        LoadCredential = [
+          "ldap-bind-pw:${cfg.ldap.bind.passwordFile}"
+        ];
+      };
+    };
+
+    systemd.services.postfix.restartTriggers = [
+      genPasswdScript
+    ];
   };
 }

mail-server/environment.nix

@@ -14,15 +14,23 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
 
 let
   cfg = config.mailserver;
 in
 {
-  config = with cfg; lib.mkIf enable {
-    environment.systemPackages = with pkgs; [
-      dovecot openssh postfix rspamd
-    ] ++ (if certificateScheme == "selfsigned" then [ openssl ] else []);
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [
+      config.services.dovecot2.package
+      pkgs.openssh
+      config.services.postfix.package
+      config.services.rspamd.package
+    ];
   };
 }

mail-server/kresd.nix

@@ -24,4 +24,3 @@ in
     services.kresd.enable = true;
   };
 }
-

mail-server/networking.nix

@@ -20,18 +20,19 @@ let
   cfg = config.mailserver;
 in
 {
-  config = with cfg; lib.mkIf (enable && openFirewall) {
+  config = lib.mkIf (cfg.enable && cfg.openFirewall) {
 
     networking.firewall = {
-      allowedTCPPorts = [ 25 ]
-        ++ lib.optional enableSubmission 587
-        ++ lib.optional enableSubmissionSsl 465
-        ++ lib.optional enableImap 143
-        ++ lib.optional enableImapSsl 993
-        ++ lib.optional enablePop3 110
-        ++ lib.optional enablePop3Ssl 995
-        ++ lib.optional enableManageSieve 4190
-        ++ lib.optional (certificateScheme == "acme-nginx") 80;
+      allowedTCPPorts = [
+        25
+      ]
+      ++ lib.optional cfg.enableSubmission 587
+      ++ lib.optional cfg.enableSubmissionSsl 465
+      ++ lib.optional cfg.enableImap 143
+      ++ lib.optional cfg.enableImapSsl 993
+      ++ lib.optional cfg.enablePop3 110
+      ++ lib.optional cfg.enablePop3Ssl 995
+      ++ lib.optional cfg.enableManageSieve 4190;
     };
   };
 }

mail-server/nginx.nix

@@ -1,42 +0,0 @@
-#  nixos-mailserver: a simple mail server
-#  Copyright (C) 2016-2018  Robin Raymond
-#
-#  This program is free software: you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation, either version 3 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program. If not, see <http://www.gnu.org/licenses/>
-
-
-{ config, pkgs, lib, ... }:
-
-with (import ./common.nix { inherit config lib pkgs; });
-
-let
-  cfg = config.mailserver;
-in
-{
-  config = lib.mkIf (cfg.enable && (cfg.certificateScheme == "acme" || cfg.certificateScheme == "acme-nginx")) {
-    services.nginx = lib.mkIf (cfg.certificateScheme == "acme-nginx") {
-      enable = true;
-      virtualHosts."${cfg.fqdn}" = {
-        serverName = cfg.fqdn;
-        serverAliases = cfg.certificateDomains;
-        forceSSL = true;
-        enableACME = true;
-      };
-    };
-
-    security.acme.certs."${cfg.acmeCertificateName}".reloadServices = [
-      "postfix.service"
-      "dovecot2.service"
-    ];
-  };
-}

mail-server/postfix.nix

@@ -14,84 +14,140 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
+{
+  config,
+  options,
+  pkgs,
+  lib,
+  ...
+}:
 
-with (import ./common.nix { inherit config pkgs lib; });
+with (import ./common.nix {
+  inherit
+    config
+    options
+    lib
+    pkgs
+    ;
+});
 
 let
   inherit (lib.strings) concatStringsSep;
   cfg = config.mailserver;
 
+  iniFormat = pkgs.formats.iniWithGlobalSection { };
+
   # Merge several lookup tables. A lookup table is a attribute set where
   # - the key is an address (user@example.com) or a domain (@example.com)
   # - the value is a list of addresses
   mergeLookupTables = tables: lib.zipAttrsWith (_: v: lib.flatten v) tables;
 
   # valiases_postfix :: Map String [String]
-  valiases_postfix = mergeLookupTables (lib.flatten (lib.mapAttrsToList
-    (name: value:
-      let to = name;
-      in map (from: {"${from}" = to;}) (value.aliases ++ lib.singleton name))
-    cfg.loginAccounts));
-  regex_valiases_postfix = mergeLookupTables (lib.flatten (lib.mapAttrsToList
-    (name: value:
-      let to = name;
-      in map (from: {"${from}" = to;}) value.aliasesRegexp)
-    cfg.loginAccounts));
+  valiases_postfix = mergeLookupTables (
+    lib.flatten (
+      lib.mapAttrsToList (
+        name: value:
+        let
+          to = name;
+        in
+        map (from: { "${from}" = to; }) (value.aliases ++ lib.singleton name)
+      ) cfg.accounts
+    )
+  );
+  regex_valiases_postfix = mergeLookupTables (
+    lib.flatten (
+      lib.mapAttrsToList (
+        name: value:
+        let
+          to = name;
+        in
+        map (from: { "${from}" = to; }) value.aliasesRegexp
+      ) cfg.accounts
+    )
+  );
 
   # catchAllPostfix :: Map String [String]
-  catchAllPostfix =  mergeLookupTables (lib.flatten (lib.mapAttrsToList
-    (name: value:
-      let to = name;
-      in map (from: {"@${from}" = to;}) value.catchAll)
-      cfg.loginAccounts));
+  catchAllPostfix = mergeLookupTables (
+    lib.flatten (
+      lib.mapAttrsToList (
+        name: value:
+        let
+          to = name;
+        in
+        map (from: { "@${from}" = to; }) value.catchAll
+      ) cfg.accounts
+    )
+  );
 
   # all_valiases_postfix :: Map String [String]
-  all_valiases_postfix = mergeLookupTables [valiases_postfix extra_valiases_postfix];
+  all_valiases_postfix = mergeLookupTables [
+    valiases_postfix
+    extra_valiases_postfix
+  ];
 
   # attrsToLookupTable :: Map String (Either String [ String ]) -> Map String [String]
-  attrsToLookupTable = aliases: let
-    lookupTables = lib.mapAttrsToList (from: to: {"${from}" = to;}) aliases;
-  in mergeLookupTables lookupTables;
+  attrsToLookupTable =
+    aliases:
+    let
+      lookupTables = lib.mapAttrsToList (from: to: { "${from}" = to; }) aliases;
+    in
+    mergeLookupTables lookupTables;
 
   # extra_valiases_postfix :: Map String [String]
-  extra_valiases_postfix = attrsToLookupTable cfg.extraVirtualAliases;
+  extra_valiases_postfix = attrsToLookupTable cfg.aliases;
 
   # forwards :: Map String [String]
   forwards = attrsToLookupTable cfg.forwards;
 
   # lookupTableToString :: Map String [String] -> String
-  lookupTableToString = attrs: let
-    valueToString = value: lib.concatStringsSep ", " value;
-  in lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value: "${name} ${valueToString value}") attrs);
+  lookupTableToString =
+    attrs:
+    let
+      valueToString = value: lib.concatStringsSep ", " value;
+    in
+    lib.concatStringsSep "\n" (
+      lib.mapAttrsToList (name: value: "${name} ${valueToString value}") attrs
+    );
 
   # valiases_file :: Path
-  valiases_file = let
-    content = lookupTableToString (mergeLookupTables [all_valiases_postfix catchAllPostfix]);
-  in builtins.toFile "valias" content;
+  valiases_file =
+    let
+      content = lookupTableToString (mergeLookupTables [
+        all_valiases_postfix
+        catchAllPostfix
+      ]);
+    in
+    builtins.toFile "valias" content;
 
-  regex_valiases_file = let
-    content = lookupTableToString regex_valiases_postfix;
-  in builtins.toFile "regex_valias" content;
+  regex_valiases_file =
+    let
+      content = lookupTableToString regex_valiases_postfix;
+    in
+    builtins.toFile "regex_valias" content;
 
   # denied_recipients_postfix :: [ String ]
-  denied_recipients_postfix = (map
-    (acct: "${acct.name} REJECT ${acct.sendOnlyRejectMessage}")
-    (lib.filter (acct: acct.sendOnly) (lib.attrValues cfg.loginAccounts)));
-  denied_recipients_file = builtins.toFile "denied_recipients" (lib.concatStringsSep "\n" denied_recipients_postfix);
+  denied_recipients_postfix = map (acct: "${acct.name} REJECT ${acct.sendOnlyRejectMessage}") (
+    lib.filter (acct: acct.sendOnly) (lib.attrValues cfg.accounts)
+  );
+  denied_recipients_file = builtins.toFile "denied_recipients" (
+    lib.concatStringsSep "\n" denied_recipients_postfix
+  );
 
-  reject_senders_postfix = (map
-    (sender:
-      "${sender} REJECT")
-    (cfg.rejectSender));
-  reject_senders_file = builtins.toFile "reject_senders" (lib.concatStringsSep "\n" (reject_senders_postfix))  ;
+  reject_senders_postfix = map (
+    sender:
+    "${sender} REJECT${
+      lib.optionalString (cfg.rejectSenderMessage != "") " ${cfg.rejectSenderMessage}"
+    }"
+  ) cfg.rejectSender;
+  reject_senders_file = builtins.toFile "reject_senders" (
+    lib.concatStringsSep "\n" reject_senders_postfix
+  );
 
-  reject_recipients_postfix = (map
-    (recipient:
-      "${recipient} REJECT")
-    (cfg.rejectRecipients));
+  reject_recipients_postfix = map (recipient: "${recipient} REJECT") cfg.rejectRecipients;
   # rejectRecipients :: [ Path ]
-  reject_recipients_file = builtins.toFile "reject_recipients" (lib.concatStringsSep "\n" (reject_recipients_postfix))  ;
+  reject_recipients_file = builtins.toFile "reject_recipients" (
+    lib.concatStringsSep "\n" reject_recipients_postfix
+  );
 
   # vhosts_file :: Path
   vhosts_file = builtins.toFile "vhosts" (concatStringsSep "\n" cfg.domains);
@@ -103,64 +159,71 @@ let
   # every alias is owned (uniquely) by its user.
   # The user's own address is already in all_valiases_postfix.
   vaccounts_file = builtins.toFile "vaccounts" (lookupTableToString all_valiases_postfix);
-  regex_vaccounts_file = builtins.toFile "regex_vaccounts" (lookupTableToString regex_valiases_postfix);
+  regex_vaccounts_file = builtins.toFile "regex_vaccounts" (
+    lookupTableToString regex_valiases_postfix
+  );
 
-  submissionHeaderCleanupRules = pkgs.writeText "submission_header_cleanup_rules" (''
-     # Removes sensitive headers from mails handed in via the submission port.
-     # See https://thomas-leister.de/mailserver-debian-stretch/
-     # Uses "pcre" style regex.
+  submissionHeaderCleanupRules = pkgs.writeText "submission_header_cleanup_rules" (
+    ''
+      # Removes sensitive headers from mails handed in via the submission port.
+      # See https://thomas-leister.de/mailserver-debian-stretch/
+      # Uses "pcre" style regex.
 
-     /^Received:/            IGNORE
-     /^X-Originating-IP:/    IGNORE
-     /^X-Mailer:/            IGNORE
-     /^User-Agent:/          IGNORE
-     /^X-Enigmail:/          IGNORE
-  '' + lib.optionalString cfg.rewriteMessageId ''
+      /^Received:/            IGNORE
+      /^X-Originating-IP:/    IGNORE
+      /^X-Mailer:/            IGNORE
+      /^User-Agent:/          IGNORE
+      /^X-Enigmail:/          IGNORE
+    ''
+    + lib.optionalString cfg.rewriteMessageId ''
 
-     # Replaces the user submitted hostname with the server's FQDN to hide the
-     # user's host or network.
+      # Replaces the user submitted hostname with the server's FQDN to hide the
+      # user's host or network.
 
-     /^Message-ID:\s+<(.*?)@.*?>/ REPLACE Message-ID: <$1@${cfg.fqdn}>
-  '');
+      /^Message-ID:\s+<(.*?)@.*?>/ REPLACE Message-ID: <$1@${cfg.fqdn}>
+    ''
+  );
 
   smtpdMilters = [ "unix:/run/rspamd/rspamd-milter.sock" ];
 
   mappedFile = name: "hash:/var/lib/postfix/conf/${name}";
   mappedRegexFile = name: "pcre:/var/lib/postfix/conf/${name}";
 
-  submissionOptions =
-    {
-      smtpd_tls_security_level = "encrypt";
-      smtpd_sasl_auth_enable = "yes";
-      smtpd_sasl_type = "dovecot";
-      smtpd_sasl_path = "/run/dovecot2/auth";
-      smtpd_sasl_security_options = "noanonymous";
-      smtpd_sasl_local_domain = "$myhostname";
-      smtpd_client_restrictions = "permit_sasl_authenticated,reject";
-      smtpd_sender_login_maps = "hash:/etc/postfix/vaccounts${lib.optionalString cfg.ldap.enable ",ldap:${ldapSenderLoginMapFile}"}${lib.optionalString (regex_valiases_postfix != {}) ",pcre:/etc/postfix/regex_vaccounts"}";
-      smtpd_sender_restrictions = "reject_sender_login_mismatch";
-      smtpd_recipient_restrictions = "reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject";
-      cleanup_service_name = "submission-header-cleanup";
-    };
+  submissionOptions = {
+    smtpd_tls_security_level = "encrypt";
+    smtpd_sasl_auth_enable = "yes";
+    smtpd_sasl_type = "dovecot";
+    smtpd_sasl_path = "/run/dovecot2/auth";
+    smtpd_sasl_security_options = "noanonymous";
+    smtpd_sasl_local_domain = "$myhostname";
+    smtpd_client_restrictions = "permit_sasl_authenticated,reject";
+    smtpd_sender_login_maps = "hash:/etc/postfix/vaccounts${lib.optionalString cfg.ldap.enable ",ldap:${ldapSenderLoginMapFile}"}${
+      lib.optionalString (regex_valiases_postfix != { }) ",pcre:/etc/postfix/regex_vaccounts"
+    }";
+    smtpd_sender_restrictions = "reject_sender_login_mismatch";
+    smtpd_recipient_restrictions = "reject_non_fqdn_recipient,reject_unknown_recipient_domain,permit_sasl_authenticated,reject";
+    cleanup_service_name = "submission-header-cleanup";
+  };
 
   commonLdapConfig = ''
     server_host = ${lib.concatStringsSep " " cfg.ldap.uris}
     start_tls = ${if cfg.ldap.startTls then "yes" else "no"}
     version = 3
-    tls_ca_cert_file = ${cfg.ldap.tlsCAFile}
+    tls_ca_cert_file = ${cfg.ldap.caFile}
     tls_require_cert = yes
 
-    search_base = ${cfg.ldap.searchBase}
-    scope = ${cfg.ldap.searchScope}
+    search_base = ${cfg.ldap.base}
+    scope = ${cfg.ldap.scope}
 
     bind = yes
     bind_dn = ${cfg.ldap.bind.dn}
   '';
 
+  # Enforce a mapping between SMTP user and envelope sender address
   ldapSenderLoginMap = pkgs.writeText "ldap-sender-login-map.cf" ''
     ${commonLdapConfig}
     query_filter = ${cfg.ldap.postfix.filter}
-    result_attribute = ${cfg.ldap.postfix.mailAttribute}
+    result_attribute = ${cfg.ldap.attributes.username}
   '';
   ldapSenderLoginMapFile = "/run/postfix/ldap-sender-login-map.cf";
   appendPwdInSenderLoginMap = appendLdapBindPwd {
@@ -171,10 +234,11 @@ let
     destination = ldapSenderLoginMapFile;
   };
 
+  # Check whether a recipient address exists, before accepting mail for it
   ldapVirtualMailboxMap = pkgs.writeText "ldap-virtual-mailbox-map.cf" ''
     ${commonLdapConfig}
     query_filter = ${cfg.ldap.postfix.filter}
-    result_attribute = ${cfg.ldap.postfix.uidAttribute}
+    result_attribute = ${cfg.ldap.attributes.username}
   '';
   ldapVirtualMailboxMapFile = "/run/postfix/ldap-virtual-mailbox-map.cf";
   appendPwdInVirtualMailboxMap = appendLdapBindPwd {
@@ -186,20 +250,66 @@ let
   };
 in
 {
-  config = with cfg; lib.mkIf enable {
+  config = lib.mkIf cfg.enable {
+    # SMTP TLS error reporting (RFC 8460)
+    services.tlsrpt = {
+      inherit (cfg.tlsrpt) enable;
+      configurePostfix = true;
+      reportd.settings = {
+        organization_name = cfg.systemName;
+        contact_info = "${cfg.systemContact}";
+        sender_address = "noreply-tlsrpt@${cfg.systemDomain}";
+      };
+    };
+
+    # SMTP client policy mapping for DANE (RFC 6698) and MTA-STS (RFC 8461)
+    services.postfix-tlspol = {
+      enable = true;
+      configurePostfix = true;
+    };
+
+    # Sender Rewriting Scheme (https://www.libsrs2.net/srs/srs.pdf)
+    services.postsrsd = {
+      inherit (cfg.srs) enable;
+      configurePostfix = true;
+      settings = {
+        domains = lib.unique (
+          [
+            cfg.fqdn
+            cfg.sendingFqdn
+            cfg.systemDomain
+          ]
+          ++ cfg.domains
+        );
+        separator = "=";
+        srs-domain = cfg.srs.domain;
+      };
+    };
+
+    security.acme.certs = lib.mkIf withACME {
+      ${cfg.x509.useACMEHost} = {
+        reloadServices = [ "postfix.service" ];
+      };
+    };
+
+    systemd.services.postfix.reloadTriggers = lib.mkIf (!withACME) [
+      x509CertificateFile
+      x509PrivateKeyFile
+    ];
 
     systemd.services.postfix-setup = lib.mkIf cfg.ldap.enable {
       preStart = ''
         ${appendPwdInVirtualMailboxMap}
         ${appendPwdInSenderLoginMap}
       '';
-      restartTriggers = [ appendPwdInVirtualMailboxMap appendPwdInSenderLoginMap ];
+      restartTriggers = [
+        appendPwdInVirtualMailboxMap
+        appendPwdInSenderLoginMap
+      ];
     };
 
     services.postfix = {
       enable = true;
-      hostname = "${sendingFqdn}";
-      networksStyle = "host";
       mapFiles."valias" = valiases_file;
       mapFiles."regex_valias" = regex_valiases_file;
       mapFiles."vaccounts" = vaccounts_file;
@@ -207,50 +317,51 @@ in
       mapFiles."denied_recipients" = denied_recipients_file;
       mapFiles."reject_senders" = reject_senders_file;
       mapFiles."reject_recipients" = reject_recipients_file;
-      sslCert = certificatePath;
-      sslKey = keyPath;
       enableSubmission = cfg.enableSubmission;
       enableSubmissions = cfg.enableSubmissionSsl;
-      virtual = lookupTableToString (mergeLookupTables [all_valiases_postfix catchAllPostfix forwards]);
+      virtual = lookupTableToString (mergeLookupTables [
+        all_valiases_postfix
+        catchAllPostfix
+        forwards
+      ]);
 
-      config = {
-        # Extra Config
-        mydestination = "";
+      settings.main = {
+        myhostname = cfg.sendingFqdn;
+        mydestination = ""; # disable local mail delivery
         recipient_delimiter = cfg.recipientDelimiter;
-        smtpd_banner = "${fqdn} ESMTP NO UCE";
+        smtpd_banner = "${cfg.fqdn} ESMTP NO UCE";
         disable_vrfy_command = true;
-        message_size_limit = toString cfg.messageSizeLimit;
+        message_size_limit = cfg.messageSizeLimit;
 
         # virtual mail system
-        virtual_uid_maps = "static:5000";
-        virtual_gid_maps = "static:5000";
-        virtual_mailbox_base = mailDirectory;
         virtual_mailbox_domains = vhosts_file;
         virtual_mailbox_maps = [
           (mappedFile "valias")
-        ] ++ lib.optionals (cfg.ldap.enable) [
+        ]
+        ++ lib.optionals cfg.ldap.enable [
           "ldap:${ldapVirtualMailboxMapFile}"
-        ] ++ lib.optionals (regex_valiases_postfix != {}) [
+        ]
+        ++ lib.optionals (regex_valiases_postfix != { }) [
           (mappedRegexFile "regex_valias")
         ];
-        virtual_alias_maps = lib.mkAfter (lib.optionals (regex_valiases_postfix != {}) [
-          (mappedRegexFile "regex_valias")
-        ]);
+        virtual_alias_maps = lib.mkAfter (
+          lib.optionals (regex_valiases_postfix != { }) [
+            (mappedRegexFile "regex_valias")
+          ]
+        );
         virtual_transport = "lmtp:unix:/run/dovecot2/dovecot-lmtp";
+
         # Avoid leakage of X-Original-To, X-Delivered-To headers between recipients
         lmtp_destination_recipient_limit = "1";
 
-        # Opportunistic DANE support
-        # https://www.postfix.org/postconf.5.html#smtp_tls_security_level
-        smtp_dns_support_level = "dnssec";
-        smtp_tls_security_level = "dane";
-
         # sasl with dovecot
         smtpd_sasl_type = "dovecot";
         smtpd_sasl_path = "/run/dovecot2/auth";
         smtpd_sasl_auth_enable = true;
         smtpd_relay_restrictions = [
-          "permit_mynetworks" "permit_sasl_authenticated" "reject_unauth_destination"
+          "permit_mynetworks"
+          "permit_sasl_authenticated"
+          "reject_unauth_destination"
         ];
 
         # reject selected senders
@@ -262,56 +373,135 @@ in
           # reject selected recipients
           "check_recipient_access ${mappedFile "denied_recipients"}"
           "check_recipient_access ${mappedFile "reject_recipients"}"
+        ]
+        ++ lib.optionals cfg.quota.enable [
           # quota checking
           "check_policy_service unix:/run/dovecot2/quota-status"
         ];
 
-        # TLS settings, inspired by https://github.com/jeaye/nix-files
-        # Submission by mail clients is handled in submissionOptions
+        # The X509 private key followed by the corresponding certificate
+        smtpd_tls_chain_files = [
+          "${x509PrivateKeyFile}"
+          "${x509CertificateFile}"
+        ];
+
+        # TLS for incoming mail is optional
         smtpd_tls_security_level = "may";
 
-        # Disable obselete protocols
-        smtpd_tls_protocols = "TLSv1.3, TLSv1.2, !TLSv1.1, !TLSv1, !SSLv2, !SSLv3";
-        smtp_tls_protocols = "TLSv1.3, TLSv1.2, !TLSv1.1, !TLSv1, !SSLv2, !SSLv3";
-        smtpd_tls_mandatory_protocols = "TLSv1.3, TLSv1.2, !TLSv1.1, !TLSv1, !SSLv2, !SSLv3";
-        smtp_tls_mandatory_protocols = "TLSv1.3, TLSv1.2, !TLSv1.1, !TLSv1, !SSLv2, !SSLv3";
+        # But required for authentication attempts
+        smtpd_tls_auth_only = true;
 
-        smtp_tls_ciphers = "high";
+        # TLS versions supported for the SMTP server
+        smtpd_tls_protocols = ">=TLSv1";
+        smtpd_tls_mandatory_protocols = ">=TLSv1";
+
+        # Require ciphersuites that OpenSSL classifies as "High"
         smtpd_tls_ciphers = "high";
-        smtp_tls_mandatory_ciphers = "high";
         smtpd_tls_mandatory_ciphers = "high";
 
-        # Disable deprecated ciphers
-        smtpd_tls_mandatory_exclude_ciphers = "MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL";
-        smtpd_tls_exclude_ciphers = "MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL";
-        smtp_tls_mandatory_exclude_ciphers = "MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL";
-        smtp_tls_exclude_ciphers = "MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL";
+        # Enable DNSSEC/DANE support for outgoing SMTP connections
+        # https://www.postfix.org/postconf.5.html#smtp_tls_security_level
+        smtp_dns_support_level = "dnssec";
+        smtp_tls_security_level = "dane";
 
-        tls_preempt_cipherlist = true;
+        # TLS versions supported for the SMTP client
+        smtp_tls_protocols = ">=TLSv1.2";
+        smtp_tls_mandatory_protocols = ">=TLSv1.2";
+
+        # Require ciphersuites that OpenSSL classifies as "High"
+        smtp_tls_ciphers = "high";
+        smtp_tls_mandatory_ciphers = "high";
+
+        tls_config_file =
+          let
+            mkGroupString = groups: concatStringsSep " / " (map (concatStringsSep ":") groups);
+          in
+          iniFormat.generate "postfix-openssl.cnf" {
+            globalSection.postfix = "postfix_settings";
+            sections = {
+              postfix_settings.ssl_conf = "postfix_ssl_settings";
+              postfix_ssl_settings.system_default = "baseline_postfix_settings";
+              baseline_postfix_settings = {
+                # Allow all TLSv1.3 cipher suites
+                Ciphersuites = concatStringsSep ":" [
+                  "TLS_AES_256_GCM_SHA384"
+                  "TLS_AES_128_GCM_SHA256"
+                  "TLS_CHACHA20_POLY1305_SHA256"
+                ];
+
+                # Full list: openssl list -tls-groups
+                # Restrict and prioritize the following curves in the given order
+                # Excludes curves that have no widespread support, so we don't bloat the handshake needlessly.
+                # https://www.postfix.org/postconf.5.html#tls_eecdh_auto_curves
+                Groups = mkGroupString [
+                  [ "*X25519MLKEM768" ]
+                  [ "*X25519" ]
+                  [ "SecP256r1MLKEM768" ]
+                  [
+                    "P-256"
+                    "P-384"
+                  ]
+                ];
+                SignatureAlgorithms = concatStringsSep ":" [
+                  # Full list: openssl list -tls-signature-algorithms
+                  # Reduced to algorithms with key material supported in CA/B
+                  # baseline requirements and excluding deprecated algorithms
+                  # like SHA1.
+
+                  # EcDSA certificates
+                  # https://cabforum.org/working-groups/server/baseline-requirements/requirements/#71312-ecdsa
+                  "ecdsa_secp256r1_sha256"
+                  "ecdsa_secp384r1_sha384"
+                  "ecdsa_secp521r1_sha512"
+
+                  # RSA certificates
+                  # https://cabforum.org/working-groups/server/baseline-requirements/requirements/#71311-rsa
+                  "rsa_pss_rsae_sha256"
+                  "rsa_pss_rsae_sha384"
+                  "rsa_pss_rsae_sha512"
+                  "rsa_pss_pss_sha256"
+                  "rsa_pss_pss_sha384"
+                  "rsa_pss_pss_sha512"
+                  "rsa_pkcs1_sha256"
+                  "rsa_pkcs1_sha384"
+                  "rsa_pkcs1_sha512"
+                ];
+              };
+            };
+          };
+        tls_config_name = "postfix";
+
+        # Algorithm selection happens through `tls_config_file` instead.
+        tls_eecdh_auto_curves = [ ];
+        tls_ffdhe_auto_groups = [ ];
+
+        # Require AEAD & ECDHE for TLSv1.2.
+        tls_high_cipherlist = concatStringsSep ":" [
+          "ECDHE-ECDSA-AES256-GCM-SHA384"
+          "ECDHE-RSA-AES256-GCM-SHA384"
+          "ECDHE-ECDSA-AES128-GCM-SHA256"
+          "ECDHE-RSA-AES128-GCM-SHA256"
+          "ECDHE-ECDSA-CHACHA20-POLY1305"
+          "ECDHE-RSA-CHACHA20-POLY1305"
+        ];
+
+        # As long as all cipher suites are considered safe, let the client use its preferred cipher
+        tls_preempt_cipherlist = false;
 
-        # Allowing AUTH on a non encrypted connection poses a security risk
-        smtpd_tls_auth_only = true;
         # Log only a summary message on TLS handshake completion
         smtp_tls_loglevel = "1";
         smtpd_tls_loglevel = "1";
 
-        # Configure a non blocking source of randomness
-        tls_random_source = "dev:/dev/urandom";
-
         smtpd_milters = smtpdMilters;
-        non_smtpd_milters = lib.mkIf cfg.dkimSigning [ "unix:/run/rspamd/rspamd-milter.sock" ];
+        non_smtpd_milters = lib.mkIf cfg.dkim.enable [ "unix:/run/rspamd/rspamd-milter.sock" ];
         milter_protocol = "6";
         milter_mail_macros = "i {mail_addr} {client_addr} {client_name} {auth_authen}";
-
-        # Fix for https://www.postfix.org/smtp-smuggling.html
-        smtpd_forbid_bare_newline = cfg.smtpdForbidBareNewline;
-        smtpd_forbid_bare_newline_exclusions = "$mynetworks";
       };
 
       submissionOptions = submissionOptions;
       submissionsOptions = submissionOptions;
 
-      masterConfig = {
+      settings.master = {
         "lmtp" = {
           # Add headers when delivering, see http://www.postfix.org/smtp.8.html
           # D => Delivered-To, O => X-Original-To, R => Return-Path
@@ -323,7 +513,10 @@ in
           chroot = false;
           maxproc = 0;
           command = "cleanup";
-          args = ["-o" "header_checks=pcre:${submissionHeaderCleanupRules}"];
+          args = [
+            "-o"
+            "header_checks=pcre:${submissionHeaderCleanupRules}"
+          ];
         };
       };
     };

mail-server/rsnapshot.nix

@@ -14,11 +14,19 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
-
-with lib;
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
 
 let
+  inherit (lib)
+    optionalString
+    mkIf
+    ;
+
   cfg = config.mailserver;
 
   preexecDefined = cfg.backup.cmdPreexec != null;
@@ -38,7 +46,8 @@ let
     ${cfg.backup.cmdPostexec}
   '';
   postexecString = optionalString postexecDefined "cmd_postexec	${postexecWrapped}";
-in {
+in
+{
   config = mkIf (cfg.enable && cfg.backup.enable) {
     services.rsnapshot = {
       enable = true;
@@ -52,7 +61,7 @@ in {
         retain	hourly	${toString cfg.backup.retain.hourly}
         retain	daily	${toString cfg.backup.retain.daily}
         retain	weekly	${toString cfg.backup.retain.weekly}
-        backup	${cfg.mailDirectory}/	localhost/
+        backup	${cfg.storage.path}/	localhost/
       '';
     };
   };

mail-server/rspamd.nix

@@ -14,106 +14,217 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
 
 let
   cfg = config.mailserver;
 
   postfixCfg = config.services.postfix;
   rspamdCfg = config.services.rspamd;
-  rspamdSocket = "rspamd.service";
 
+  rspamdPkg = config.services.rspamd.package;
   rspamdUser = config.services.rspamd.user;
   rspamdGroup = config.services.rspamd.group;
 
-  createDkimKeypair = domain: let
-    privateKey = "${cfg.dkimKeyDirectory}/${domain}.${cfg.dkimSelector}.key";
-    publicKey = "${cfg.dkimKeyDirectory}/${domain}.${cfg.dkimSelector}.txt";
-  in pkgs.writeShellScript "dkim-keygen-${domain}" ''
-    if [ ! -f "${privateKey}" ]
-    then
-      ${lib.getExe' pkgs.rspamd "rspamadm"} dkim_keygen \
-        --domain "${domain}" \
-        --selector "${cfg.dkimSelector}" \
-        --type "${cfg.dkimKeyType}" \
-        --bits ${toString cfg.dkimKeyBits} \
-        --privkey "${privateKey}" > "${publicKey}"
-      chmod 0644 "${publicKey}"
-      echo "Generated key for domain ${domain} and selector ${cfg.dkimSelector}"
-    fi
-  '';
+  createDkimKeypair =
+    {
+      domain,
+      selector,
+      type,
+      bits,
+      ...
+    }:
+    let
+      privkey = "${cfg.dkim.keyDirectory}/${domain}.${selector}.key";
+      pubkey = "${cfg.dkim.keyDirectory}/${domain}.${selector}.txt";
+    in
+    pkgs.writeShellScript "dkim-keygen-${domain}-${selector}" ''
+      if [ ! -f "${privkey}" ]
+      then
+        ${lib.getExe' rspamdPkg "rspamadm"} dkim_keygen ${
+          lib.cli.toCommandLineShellGNU { } {
+            inherit
+              domain
+              selector
+              type
+              bits
+              privkey
+              ;
+          }
+        } > "${pubkey}"
+        chmod 0644 "${pubkey}"
+        echo "Generated key for domain ${domain} and selector ${selector}"
+      fi
+    '';
+
+  mailDomains = lib.unique (
+    # primary mailserver domains
+    config.mailserver.domains
+    # all dkim domains, even extra domains specified
+    ++ lib.attrNames cfg.dkim.domains
+    # and the srs domain, if one is configured
+    ++ lib.optionals (cfg.srs.domain != null) [ cfg.srs.domain ]
+  );
+
+  dkimKeys = lib.concatMap (
+    domain:
+    let
+      configuredSelectors = config.mailserver.dkim.domains.${domain}.selectors or { };
+
+      finalSelectors =
+        if configuredSelectors == { } then
+          # synthesize default dkim key, if none configured
+          {
+            "${config.mailserver.dkim.defaults.selector}" = {
+              keyType = null;
+              keyLength = null;
+              keyFile = null;
+            };
+          }
+        else
+          configuredSelectors;
+    in
+    lib.mapAttrsToList (selector: settings: rec {
+      inherit domain selector;
+      keyFile = settings.keyFile;
+      keyPath = if keyFile != null then keyFile else "${cfg.dkim.keyDirectory}/${domain}.${selector}.key";
+      bits =
+        if settings.keyLength != null then
+          settings.keyLength
+        else
+          config.mailserver.dkim.defaults.keyLength;
+      type =
+        if settings.keyType != null then settings.keyType else config.mailserver.dkim.defaults.keyType;
+    }) finalSelectors
+  ) mailDomains;
+
+  dkimKeysToGenerate = lib.filter (key: key.keyFile == null) dkimKeys;
+
+  dkimKeysByDomain = lib.groupBy (item: item.domain) dkimKeys;
 in
 {
-  config = with cfg; lib.mkIf enable {
+  config = lib.mkIf cfg.enable {
     environment.systemPackages = lib.mkBefore [
-      (pkgs.runCommand "rspamc-wrapped" {
-        nativeBuildInputs = with pkgs; [ makeWrapper ];
-       }''
-        makeWrapper ${pkgs.rspamd}/bin/rspamc $out/bin/rspamc \
-          --add-flags "-h /run/rspamd/worker-controller.sock"
-      '')
+      (pkgs.runCommand "rspamc-wrapped"
+        {
+          nativeBuildInputs = with pkgs; [ makeWrapper ];
+        }
+        ''
+          makeWrapper ${lib.getExe' rspamdPkg "rspamc"} $out/bin/rspamc \
+            --add-flags "-h /run/rspamd/worker-controller.sock"
+        ''
+      )
     ];
 
     services.rspamd = {
       enable = true;
-      inherit debug;
+      debug = cfg.debug.rspamd;
       locals = {
-          "milter_headers.conf" = { text = ''
-              extended_spam_headers = true;
-          ''; };
-          "redis.conf" = { text = ''
-              servers = "${if cfg.redis.port == null
-                then
-                  cfg.redis.address
-                else
-                  "${cfg.redis.address}:${toString cfg.redis.port}"}";
-          '' + (lib.optionalString (cfg.redis.password != null) ''
-              password = "${cfg.redis.password}";
-          ''); };
-          "classifier-bayes.conf" = { text = ''
-              cache {
-                backend = "redis";
-              }
-          ''; };
-          "antivirus.conf" = lib.mkIf cfg.virusScanning { text = ''
-              clamav {
-                action = "reject";
-                symbol = "CLAM_VIRUS";
-                type = "clamav";
-                log_clean = true;
-                servers = "/run/clamav/clamd.ctl";
-                scan_mime_parts = false; # scan mail as a whole unit, not parts. seems to be needed to work at all
-              }
-          ''; };
-          "dkim_signing.conf" = { text = ''
-            enabled = ${lib.boolToString cfg.dkimSigning};
-            path = "${cfg.dkimKeyDirectory}/$domain.$selector.key";
-            selector = "${cfg.dkimSelector}";
+        "milter_headers.conf" = {
+          text = ''
+            use = [ "authentication-results" ];
+            extended_spam_headers = true;
+          '';
+        };
+        "redis.conf" = {
+          text = ''
+            servers = "${
+              if cfg.redis.port == null then
+                cfg.redis.address
+              else
+                "${cfg.redis.address}:${toString cfg.redis.port}"
+            }";
+          ''
+          + (lib.optionalString (cfg.redis.password != null) ''
+            password = "${cfg.redis.password}";
+          '');
+        };
+        "classifier-bayes.conf" = {
+          text = ''
+            cache {
+              backend = "redis";
+            }
+          '';
+        };
+        "antivirus.conf" = lib.mkIf cfg.virusScanning {
+          text = ''
+            clamav {
+              action = "reject";
+              symbol = "CLAM_VIRUS";
+              type = "clamav";
+              log_clean = true;
+              servers = "/run/clamav/clamd.ctl";
+              scan_mime_parts = false; # scan mail as a whole unit, not parts. seems to be needed to work at all
+            }
+          '';
+        };
+        "dkim_signing.conf" = {
+          text = ''
+            enabled = ${lib.boolToString cfg.dkim.enable};
+            # Only sign explicitly configured domains
+            try_fallback = false;
             # Allow for usernames w/o domain part
-            allow_username_mismatch = true
-          ''; };
-          "dmarc.conf" = { text = ''
-              ${lib.optionalString cfg.dmarcReporting.enable ''
+            allow_username_mismatch = true;
+            # Don't normalize DKIM key selection for subdomains
+            use_esld = false;
+
+            domain {
+            ${lib.concatStringsSep "\n\n" (
+              map (domain: ''
+                ${domain} {
+                  selectors [
+                ${lib.concatStringsSep ",\n" (
+                  map (selector: ''
+                    {
+                      path: "${selector.keyPath}";
+                      selector: "${selector.selector}";
+                    }'') dkimKeysByDomain.${domain}
+                )}
+                  ]
+                }
+              '') (lib.attrNames dkimKeysByDomain)
+            )}
+            }
+          '';
+        };
+        "dmarc.conf" = {
+          text = ''
+            ${lib.optionalString cfg.dmarcReporting.enable ''
               reporting {
                 enabled = true;
-                email = "${cfg.dmarcReporting.email}";
-                domain = "${cfg.dmarcReporting.domain}";
-                org_name = "${cfg.dmarcReporting.organizationName}";
-                from_name = "${cfg.dmarcReporting.fromName}";
-                msgid_from = "${cfg.dmarcReporting.domain}";
-                ${lib.optionalString (cfg.dmarcReporting.excludeDomains != []) ''
+                email = "noreply-dmarc@${cfg.systemDomain}";
+                domain = "${cfg.systemDomain}";
+                org_name = "${cfg.systemName}";
+                from_name = "${cfg.systemName}";
+                msgid_from = "${cfg.systemDomain}";
+                ${lib.optionalString (cfg.dmarcReporting.excludeDomains != [ ]) ''
                   exclude_domains = ${builtins.toJSON cfg.dmarcReporting.excludeDomains};
                 ''}
               }''}
-          ''; };
+          '';
+        };
+      };
+      overrides = {
+        "options.inc" = {
+          text = ''
+            local_addrs = [::1/128, 127.0.0.0/8]
+          '';
+        };
       };
 
       workers.rspamd_proxy = {
         type = "rspamd_proxy";
-        bindSockets = [{
-          socket = "/run/rspamd/rspamd-milter.sock";
-          mode = "0664";
-        }];
+        bindSockets = [
+          {
+            socket = "/run/rspamd/rspamd-milter.sock";
+            mode = "0664";
+          }
+        ];
         count = 1; # Do not spawn too many processes of this type
         extraConfig = ''
           milter = yes; # Enable milter mode
@@ -128,11 +239,13 @@ in
       workers.controller = {
         type = "controller";
         count = 1;
-        bindSockets = [{
-          socket = "/run/rspamd/worker-controller.sock";
-          mode = "0666";
-        }];
-        includes = [];
+        bindSockets = [
+          {
+            socket = "/run/rspamd/worker-controller.sock";
+            mode = "0666";
+          }
+        ];
+        includes = [ ];
         extraConfig = ''
           static_dir = "''${WWWDIR}"; # Serve the web UI static assets
         '';
@@ -140,10 +253,10 @@ in
 
     };
 
-    services.redis.servers.rspamd.enable = lib.mkDefault true;
+    services.redis.servers.rspamd.enable = lib.mkDefault cfg.redis.configureLocally;
 
     systemd.tmpfiles.settings."10-rspamd.conf" = {
-      "${cfg.dkimKeyDirectory}" = {
+      "${cfg.dkim.keyDirectory}" = {
         d = {
           # Create /var/dkim owned by rspamd user/group
           user = rspamdUser;
@@ -164,25 +277,27 @@ in
         {
           SupplementaryGroups = [ config.services.redis.servers.rspamd.group ];
         }
-        (lib.optionalAttrs cfg.dkimSigning {
-          ExecStartPre = map createDkimKeypair cfg.domains;
-          ReadWritePaths = [ cfg.dkimKeyDirectory ];
+        (lib.optionalAttrs cfg.dkim.enable {
+          ExecStartPre = map createDkimKeypair dkimKeysToGenerate;
+          ReadWritePaths = [ cfg.dkim.keyDirectory ];
         })
       ];
     };
 
-    systemd.services.rspamd-dmarc-reporter = lib.optionalAttrs (cfg.dmarcReporting.enable) {
+    systemd.services.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
       # Explicitly select yesterday's date to work around broken
       # default behaviour when called without a date.
       # https://github.com/rspamd/rspamd/issues/4062
-      script = ''
-        ${pkgs.rspamd}/bin/rspamadm dmarc_report $(date -d "yesterday" "+%Y%m%d")
-      '';
+      script = toString [
+        (lib.getExe' rspamdPkg "rspamadm")
+        "dmarc_report"
+        "$(date -d 'yesterday' '+%Y%m%d')"
+      ];
       serviceConfig = {
         User = "${config.services.rspamd.user}";
         Group = "${config.services.rspamd.group}";
 
-        AmbientCapabilities = [];
+        AmbientCapabilities = [ ];
         CapabilityBoundingSet = "";
         DevicePolicy = "closed";
         IPAddressAllow = "localhost";
@@ -203,10 +318,17 @@ in
         ProcSubset = "pid";
         ProtectSystem = "strict";
         RemoveIPC = true;
-        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_UNIX"
+        ];
         RestrictNamespaces = true;
         RestrictRealtime = true;
         RestrictSUIDSGID = true;
+        SupplementaryGroups = lib.optionals cfg.redis.configureLocally [
+          config.services.redis.servers.rspamd.group
+        ];
         SystemCallArchitectures = "native";
         SystemCallFilter = [
           "@system-service"
@@ -216,7 +338,7 @@ in
       };
     };
 
-    systemd.timers.rspamd-dmarc-reporter = lib.optionalAttrs (cfg.dmarcReporting.enable) {
+    systemd.timers.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
       description = "Daily delivery of aggregated DMARC reports";
       wantedBy = [
         "timers.target"
@@ -229,12 +351,6 @@ in
       };
     };
 
-    systemd.services.postfix = {
-      after = [ rspamdSocket ];
-      requires = [ rspamdSocket ];
-    };
-
     users.extraUsers.${postfixCfg.user}.extraGroups = [ rspamdCfg.group ];
   };
 }
-

mail-server/systemd.nix

@@ -14,72 +14,61 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
+{
+  config,
+  options,
+  pkgs,
+  lib,
+  ...
+}:
+
+with (import ./common.nix {
+  inherit
+    config
+    options
+    lib
+    pkgs
+    ;
+});
 
 let
   cfg = config.mailserver;
-  certificatesDeps =
-    if cfg.certificateScheme == "manual" then
-      []
-    else if cfg.certificateScheme == "selfsigned" then
-      [ "mailserver-selfsigned-certificate.service" ]
-    else
-      [ "acme-finished-${cfg.fqdn}.target" ];
+  certificateDeps = lib.optionals withACME [
+    "acme-order-renew-${cfg.x509.useACMEHost}.service"
+  ];
 in
 {
-  config = with cfg; lib.mkIf enable {
-    # Create self signed certificate
-    systemd.services.mailserver-selfsigned-certificate = lib.mkIf (cfg.certificateScheme == "selfsigned") {
-      after = [ "local-fs.target" ];
-      script = ''
-        # Create certificates if they do not exist yet
-        dir="${cfg.certificateDirectory}"
-        fqdn="${cfg.fqdn}"
-        [[ $fqdn == /* ]] && fqdn=$(< "$fqdn")
-        key="$dir/key-${cfg.fqdn}.pem";
-        cert="$dir/cert-${cfg.fqdn}.pem";
+  config = lib.mkIf cfg.enable {
 
-        if [[ ! -f $key || ! -f $cert ]]; then
-            mkdir -p "${cfg.certificateDirectory}"
-            (umask 077; "${pkgs.openssl}/bin/openssl" genrsa -out "$key" 2048) &&
-                "${pkgs.openssl}/bin/openssl" req -new -key "$key" -x509 -subj "/CN=$fqdn" \
-                        -days 3650 -out "$cert"
-        fi
-      '';
-      serviceConfig = {
-        Type = "oneshot";
-        PrivateTmp = true;
-      };
-    };
-
-    # Create maildir folder before dovecot startup
-    systemd.services.dovecot2 = {
-      wants = certificatesDeps;
-      after = certificatesDeps;
-      preStart = let
-        directories = lib.strings.escapeShellArgs (
-          [ mailDirectory ]
-          ++ lib.optional (cfg.indexDir != null) cfg.indexDir
-        );
-      in ''
-        # Create mail directory and set permissions. See
-        # <https://doc.dovecot.org/main/core/config/shared_mailboxes.html#filesystem-permissions-1>.
-        # Prevent world-readable paths, even temporarily.
-        umask 007
-        mkdir -p ${directories}
-        chgrp "${vmailGroupName}" ${directories}
-        chmod 02770 ${directories}
-      '';
+    systemd.services.dovecot = {
+      wants = certificateDeps;
+      after = certificateDeps;
+      preStart =
+        let
+          directories = lib.strings.escapeShellArgs (
+            [ cfg.storage.path ] ++ lib.optional (cfg.indexDir != null) cfg.indexDir
+          );
+        in
+        ''
+          # Create mail directory and set permissions. See
+          # <https://doc.dovecot.org/main/core/config/shared_mailboxes.html#filesystem-permissions-1>.
+          # Prevent world-readable paths, even temporarily.
+          umask 007
+          mkdir -p ${directories}
+          chgrp "${cfg.storage.group}" ${directories}
+          chmod 02770 ${directories}
+        '';
     };
 
     # Postfix requires dovecot lmtp socket, dovecot auth socket and certificate to work
     systemd.services.postfix = {
-      wants = certificatesDeps;
-      after = [ "dovecot2.service" ]
-        ++ lib.optional cfg.dkimSigning "rspamd.service"
-        ++ certificatesDeps;
-      requires = [ "dovecot2.service" ]
-        ++ lib.optional cfg.dkimSigning "rspamd.service";
+      wants = certificateDeps;
+      after = [
+        "dovecot.service"
+      ]
+      ++ lib.optional cfg.dkim.enable "rspamd.service"
+      ++ certificateDeps;
+      requires = [ "dovecot.service" ] ++ lib.optional cfg.dkim.enable "rspamd.service";
     };
   };
 }

mail-server/users.nix

@@ -14,91 +14,51 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ config, pkgs, lib, ... }:
-
-with config.mailserver;
+{
+  config,
+  lib,
+  ...
+}:
 
 let
-  vmail_user = {
-    name = vmailUserName;
-    isSystemUser = true;
-    uid = vmailUID;
-    home = mailDirectory;
-    createHome = true;
-    group = vmailGroupName;
-  };
-
-
-  virtualMailUsersActivationScript = pkgs.writeScript "activate-virtual-mail-users" ''
-    #!${pkgs.stdenv.shell}
-
-    set -euo pipefail
-
-    # Prevent world-readable paths, even temporarily.
-    umask 007
-
-    # Create directory to store user sieve scripts if it doesn't exist
-    if (! test -d "${sieveDirectory}"); then
-      mkdir "${sieveDirectory}"
-      chown "${vmailUserName}:${vmailGroupName}" "${sieveDirectory}"
-      chmod 770 "${sieveDirectory}"
-    fi
-
-    # Copy user's sieve script to the correct location (if it exists).  If it
-    # is null, remove the file.
-    ${lib.concatMapStringsSep "\n" ({ name, sieveScript }:
-      if lib.isString sieveScript then ''
-        if (! test -d "${sieveDirectory}/${name}"); then
-          mkdir -p "${sieveDirectory}/${name}"
-          chown "${vmailUserName}:${vmailGroupName}" "${sieveDirectory}/${name}"
-          chmod 770 "${sieveDirectory}/${name}"
-        fi
-        cat << 'EOF' > "${sieveDirectory}/${name}/default.sieve"
-        ${sieveScript}
-        EOF
-        chown "${vmailUserName}:${vmailGroupName}" "${sieveDirectory}/${name}/default.sieve"
-      '' else ''
-        if (test -f "${sieveDirectory}/${name}/default.sieve"); then
-          rm "${sieveDirectory}/${name}/default.sieve"
-        fi
-        if (test -f "${sieveDirectory}/${name}.svbin"); then
-          rm "${sieveDirectory}/${name}/default.svbin"
-        fi
-      '') (map (user: { inherit (user) name sieveScript; })
-            (lib.attrValues loginAccounts))}
-  '';
-in {
-  config = lib.mkIf enable {
+  cfg = config.mailserver;
+in
+{
+  config = lib.mkIf cfg.enable {
     # assert that all accounts provide a password
-    assertions = (map (acct: {
-      assertion = (acct.hashedPassword != null || acct.hashedPasswordFile != null);
-      message = "${acct.name} must provide either a hashed password or a password hash file";
-    }) (lib.attrValues loginAccounts));
+    assertions = map (acct: {
+      assertion =
+        lib.length (
+          lib.filter (value: value != null) [
+            acct.hashedPassword
+            acct.hashedPasswordFile
+            acct.passwordFile
+          ]
+        ) == 1;
+      message = "Login account ${acct.name} must provide exactly one of password file, hashed password, or hashed password file";
+    }) (lib.attrValues cfg.accounts);
 
     # warn for accounts that specify both password and file
-    warnings = (map
-      (acct: "${acct.name} specifies both a password hash and hash file; hash file will be used")
-      (lib.filter
-        (acct: (acct.hashedPassword != null && acct.hashedPasswordFile != null))
-        (lib.attrValues loginAccounts)));
+    warnings =
+      map (acct: "${acct.name} specifies both a password hash and hash file; hash file will be used")
+        (
+          lib.filter (acct: (acct.hashedPassword != null && acct.hashedPasswordFile != null)) (
+            lib.attrValues cfg.accounts
+          )
+        );
 
-    # set the vmail gid to a specific value
-    users.groups = {
-      "${vmailGroupName}" = { gid = vmailUID; };
+    users.groups.${cfg.storage.group} = {
+      inherit (cfg.storage) gid;
     };
-
-    # define all users
-    users.users = {
-      "${vmail_user.name}" = lib.mkForce vmail_user;
-    };
-
-    systemd.services.activate-virtual-mail-users = {
-      wantedBy = [ "multi-user.target" ];
-      before = [ "dovecot2.service" ];
-      serviceConfig = {
-        ExecStart = virtualMailUsersActivationScript;
-      };
-      enable = true;
+    users.users.${cfg.storage.owner} = lib.mkForce {
+      inherit (cfg.storage)
+        group
+        uid
+        ;
+      name = cfg.storage.owner;
+      isSystemUser = true;
+      home = cfg.storage.path;
+      createHome = true;
     };
   };
 }

migrations/nixos-mailserver-migration-03.py

@@ -0,0 +1,146 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3
+
+import argparse
+import os
+import shutil
+import sys
+from enum import Enum
+from pathlib import Path
+from pwd import getpwnam
+
+
+class FolderLayout(Enum):
+    Default = 1
+    Folder = 2
+
+
+def check_user(vmail_root: Path):
+    owner = vmail_root.owner()
+    owner_uid = getpwnam(owner).pw_uid
+
+    if os.geteuid() == owner_uid:
+        return
+
+    try:
+        print(
+            f"Trying to switch effective user id to {owner_uid} ({owner})",
+            file=sys.stderr,
+        )
+        os.seteuid(owner_uid)
+        return
+    except PermissionError:
+        print(
+            f"Failed switching to virtual mail user. Please run this script under it, for example by using `sudo -u {owner}`)",
+            file=sys.stderr,
+        )
+    sys.exit(1)
+
+
+def is_maildir_related(path: Path, layout: FolderLayout) -> bool:
+    if path.name in [
+        "subscriptions",
+        # https://doc.dovecot.org/2.3/admin_manual/mailbox_formats/maildir/#imap-uid-mapping
+        "dovecot-uidlist",
+        # https://doc.dovecot.org/2.3/admin_manual/mailbox_formats/maildir/#imap-keywords
+        "dovecot-keywords",
+    ]:
+        return True
+    if not path.is_dir():
+        return False
+    if path.name in ["cur", "new", "tmp"]:
+        return True
+    if layout is FolderLayout.Default and path.name.startswith("."):
+        return True
+    if layout is FolderLayout.Folder:
+        if path.name in ["mail"]:
+            return False
+        return True
+
+    return False
+
+
+def mkdir(dst: Path, dry_run: bool = True):
+    print(f'mkdir "{dst}"')
+    if not dry_run:
+        # u+rwx, setgid
+        dst.mkdir(mode=0o2700)
+
+
+def move(src: Path, dst: Path, dry_run: bool = True):
+    print(f'mv "{src}" "{dst}"')
+    if not dry_run:
+        src.rename(dst)
+
+
+def delete(dst: Path, dry_run: bool = True):
+    if not dst.exists():
+        return
+
+    if dst.is_dir():
+        print(f'rm --recursive "{dst}"')
+        if not dry_run:
+            shutil.rmtree(dst)
+    else:
+        print(f'rm "{dst}"')
+        if not dry_run:
+            dst.unlink()
+
+
+def main(vmail_root: Path, layout: FolderLayout, dry_run: bool = True):
+    maildirs = {path.parent for path in vmail_root.glob("*/*/cur")}
+    maybe_delete = []
+
+    # The old maildir will be the new home directory
+    for homedir in maildirs:
+        maildir = homedir / "mail"
+        mkdir(maildir, dry_run)
+
+        for path in homedir.iterdir():
+            if is_maildir_related(path, layout):
+                move(path, maildir / path.name, dry_run)
+            else:
+                maybe_delete.append(path)
+
+    # Files that are part of the previous home directory, but now obsolete
+    for path in [
+        vmail_root / ".dovecot.lda-dupes",
+        vmail_root / ".dovecot.lda-dupes.locks",
+    ]:
+        delete(path, dry_run)
+
+    # The remaining files are likely obsolete, but should still be checked with care
+    for path in maybe_delete:
+        print(f"# rm {str(path)}")
+
+    if dry_run:
+        print("\nNo changes were made.")
+        print("Run the script with `--execute` to apply the listed changes.")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="""
+        NixOS Mailserver Migration #3: Dovecot mail directory migration
+        (https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#dovecot-mail-directory-migration)
+    """
+    )
+    parser.add_argument(
+        "vmail_root", type=Path, help="Path to the `mailserver.mailDirectory`"
+    )
+    parser.add_argument(
+        "--layout",
+        choices=["default", "folder"],
+        required=True,
+        help="Folder layout: 'default' unless `mailserver.useFsLayout` was enabled, then'folder'",
+    )
+    parser.add_argument(
+        "--execute", action="store_true", help="Actually perform changes"
+    )
+
+    args = parser.parse_args()
+
+    layout = FolderLayout.Default if args.layout == "default" else FolderLayout.Folder
+
+    check_user(args.vmail_root)
+    main(args.vmail_root, layout, not args.execute)

migrations/nixos-mailserver-migration-04.py

@@ -0,0 +1,346 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p "python3.withPackages (ps: with ps; [ ldap3 ])"
+
+import argparse
+import os
+import sys
+from pathlib import Path
+from pwd import getpwnam
+from typing import Literal, cast
+
+from ldap3 import BASE, LEVEL, SUBTREE, Connection, Server
+from ldap3.core.exceptions import LDAPException
+
+LDAPSearchScope = Literal["BASE", "LEVEL", "SUBTREE"]
+
+EXIT_OK = 0
+EXIT_ERROR = 1
+EXIT_LDAP_STARTTLS = 2
+EXIT_LDAP_BIND = 3
+
+GREEN = "32"
+YELLOW = "33"
+RED = "31"
+BOLD = "1"
+
+NO_COLOR = "NO_COLOR" in os.environ
+
+
+def color(text, code):
+    if NO_COLOR:
+        return text
+    return f"\033[{code}m{text}\033[0m"
+
+
+def check_user(vmail_root: Path):
+    owner = vmail_root.owner()
+    owner_uid = getpwnam(owner).pw_uid
+
+    if os.geteuid() == owner_uid:
+        return
+
+    try:
+        print(f"Trying to switch effective user id to {owner_uid} ({owner})")
+        os.seteuid(owner_uid)
+        return
+    except PermissionError:
+        print(
+            f"Failed switching to virtual mail user. Please run this script under it, for example by using `sudo -u {owner}`)"
+        )
+    sys.exit(1)
+
+
+def move(*, src: Path, dst: Path, dry_run: bool = True) -> bool:
+    print(f'mv "{src}" "{dst}"')
+    if not dry_run:
+        try:
+            src.rename(dst)
+        except OSError as exc:
+            print(f"Rename failed ({src=!s}, {dst=!s}): {exc}")
+            return False
+    return True
+
+
+def main(
+    *,
+    vmail_root: Path,
+    ldap_uri: str,
+    ldap_starttls: bool,
+    ldap_bind_dn: str,
+    ldap_bind_pw: str,
+    ldap_base: str,
+    ldap_scope: LDAPSearchScope,
+    ldap_filter: str,
+    ldap_attr_uuid: str,
+    dry_run: bool = True,
+    verbose: bool = False,
+):
+    # Begin with LDAP connection for fast feedback
+    server = Server(ldap_uri)
+    conn = Connection(server, ldap_bind_dn, ldap_bind_pw)
+
+    if ldap_starttls:
+        try:
+            if ldap_starttls:
+                conn.start_tls()
+        except LDAPException as exc:
+            print(color(f"LDAP connection setup failed: {exc!r}", RED))
+            sys.exit(EXIT_LDAP_STARTTLS)
+
+    if not conn.bind():
+        err = conn.result
+        print(
+            color(
+                f"""
+LDAP bind failed for {ldap_bind_dn}@{ldap_uri}
+Result: {err.get("result")} ({err.get("description")})
+Message: {err.get("message")!r}""",
+                RED,
+            )
+        )
+        sys.exit(EXIT_LDAP_BIND)
+
+    # Find existing dovecot home directories and collect account identifier
+    print(
+        color(
+            f"\nEnumerate accounts based on existing home directories in {(vmail_root / 'ldap')!s}",
+            BOLD,
+        )
+    )
+
+    skipped = 0
+    accounts = set()
+    homedirs = vmail_root.glob("ldap/*")
+    for path in homedirs:
+        if not path.is_dir():
+            print(f"- Not a directory ({path=!s}) (skipping)")
+            skipped += 1
+            continue
+        elif not (path / "mail").is_dir():
+            print(f"- No maildir in home ({path=!s}) (skipping)")
+            skipped += 1
+            continue
+
+        account = path.name
+        accounts.add(account)
+        if verbose:
+            print(f"- Home directory found ({path=!s}, {account=})")
+
+    print(
+        color(
+            f"\nFinding matching LDAP entries to retrieve `{ldap_attr_uuid}` attribute",
+            BOLD,
+        )
+    )
+
+    no_entry = 0
+    multiple_entries = 0
+    plan = {}
+    for account in sorted(accounts):
+        filter = ldap_filter % account
+        conn.search(
+            search_base=ldap_base,
+            search_filter=filter,
+            search_scope=ldap_scope,
+            attributes=[ldap_attr_uuid],
+        )
+
+        if conn.response is None:
+            print(f"- LDAP search produced no result for {filter}")
+
+        count = len(conn.entries)
+
+        if count < 1:
+            print(f"- No LDAP entry found ({account=}, {filter=}) (skipping)")
+            no_entry += 1
+            continue
+        elif count > 1:
+            print(f"- Multiple LDAP entries found ({account=}, {filter=}) (skipping)")
+            multiple_entries += 1
+            continue
+        else:
+            entry = conn.entries[0]
+            uuid = str(entry[ldap_attr_uuid].value)
+            if verbose:
+                print(f"- LDAP entry mapped ({account=}, {uuid=})")
+            plan.update({account: uuid})
+
+    print(color("\nThe following operations will be executed:", BOLD))
+    moved = 0
+    moves_failed = 0
+    for src, dst in plan.items():
+        _src = vmail_root / "ldap" / src
+        _dst = vmail_root / "ldap" / dst
+        if not move(src=_src, dst=_dst, dry_run=dry_run):
+            moves_failed += 1
+        else:
+            moved += 1
+
+    print(
+        color(
+            "\nMigration summary",
+            BOLD,
+        )
+    )
+
+    if any([skipped, no_entry, multiple_entries, not accounts, moves_failed]):
+        print("""
+We strongly recommend reviewing and remediating all potential issues before
+running with `--execute`. Specific details can be found further up.""")
+
+    if moved:
+        print(f"""
+- {color(f"{moved} home directories were migrated successfully.", GREEN)} {"(dry run)" if dry_run else ""}
+  This is great news, they are now UUID-based and will be immune to username changes!""")
+
+    if skipped and accounts:
+        print(f"""
+- {color(f"{skipped} paths in {(vmail_root / 'ldap')!s} were skipped.", YELLOW)}
+  These were not a directory or did not contain a maildir. They should be
+  reviewed but can most likely be deleted.""")
+
+    if no_entry:
+        print(f"""
+- {color(f"{no_entry} LDAP queries found no entry.", YELLOW)}
+  This could be a problem, because we cannot migrate home directories without
+  finding the LDAP entry and retrieving its {ldap_attr_uuid} field. In practice
+  this can happen if an LDAP account was deleted but its mail home directory
+  remained.""")
+
+    if multiple_entries:
+        print(f"""
+- {color(f"{multiple_entries} LDAP queries returned multiple entries.", RED)}
+  This is a problem, because we cannot decide which LDAP entry owns the home
+  directory.""")
+
+    if not accounts:
+        print(f"""
+- {color("No home directories were found.", RED)}
+  Make sure you are passing the correct `vmail_root` argument. It must match
+  your `mailserver.mailDirectory` setting.""")
+
+    if moves_failed:
+        print(f"""
+- {color("{moves_failed} home directories could not be renamed", RED)}
+  No reason to panic, but the script tried to rename a home directory and that
+  triggered and error. Check further up what went wrong.""")
+
+    if dry_run:
+        print(f"\n{color('No changes were made.', YELLOW)}")
+        print("Run the script with `--execute` to apply the listed changes.")
+
+    sys.exit(EXIT_OK if moves_failed == 0 else EXIT_ERROR)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="""
+        NixOS Mailserver Migration #4: Dovecot LDAP UUID-based home directories
+        (https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#dovecot-ldap-uuid-based-home-directory)
+        """
+    )
+    parser.add_argument(
+        "vmail_root", type=Path, help="Path to the `mailserver.mailDirectory`"
+    )
+    parser.add_argument(
+        "--ldap-uri",
+        type=str,
+        required=True,
+        help="URI for your LDAP server; ldaps://ldap1.example.com (TLS) or ldap://ldap1.example.com (Plain)",
+    )
+    parser.add_argument(
+        "--ldap-starttls",
+        action="store_true",
+        help="Enable StartTLS on plain LDAP connections",
+    )
+    parser.add_argument(
+        "--ldap-bind-dn",
+        type=str,
+        required=True,
+        help="The distinguished user allow to bind and search the LDAP server",
+    )
+    parser.add_argument(
+        "--ldap-bind-pw-file",
+        type=Path,
+        required=True,
+        help="Path to a file containing the bind password for the LDAP DN",
+    )
+    parser.add_argument(
+        "--ldap-base",
+        type=str,
+        required=True,
+        help="Base DN below which to search for LDAP accounts",
+    )
+    parser.add_argument(
+        "--ldap-scope",
+        choices=[
+            "sub",
+            "base",
+            "one",
+        ],
+        default="sub",
+        help="Scope relative to the base DN",
+    )
+    parser.add_argument(
+        "--ldap-filter",
+        default="(mail=%s)",
+        help="LDAP query that filters for an account by the name in /var/vmail/ldap/<name> field, e.g. mail=%%s or uid=%%s if the name is not an email address.",
+    )
+    parser.add_argument(
+        "--ldap-attr-uuid",
+        default="entryUUID",
+        help="UUID attribute that uniquely identifies an LDAP account across login name changes",
+    )
+    parser.add_argument(
+        "--execute", action="store_true", help="Actually perform changes"
+    )
+    parser.add_argument("--verbose", action="store_true", help="Print more details")
+
+    args = parser.parse_args()
+
+    if args.ldap_filter.count("%s") != 1:
+        print(
+            "The --ldap-filter argument must contain exactly one '%s' as a placeholder for the primary email address.",
+        )
+        sys.exit(1)
+
+    def read_ldap_bind_pw():
+        try:
+            with open(args.ldap_bind_pw_file) as fd:
+                return fd.read().strip()
+        except OSError as exc:
+            print(f"Unable to read LDAP bind password file: {exc}")
+            sys.exit(1)
+
+    ldap_bind_pw = None
+    if os.geteuid() == 0:
+        # if we're root, read before priv drop
+        ldap_bind_pw = read_ldap_bind_pw()
+
+    check_user(args.vmail_root)
+
+    if ldap_bind_pw is None:
+        ldap_bind_pw = read_ldap_bind_pw()
+
+    ldap_scope: LDAPSearchScope = cast(
+        LDAPSearchScope,
+        {
+            "sub": SUBTREE,
+            "base": BASE,
+            "one": LEVEL,
+        }[args.ldap_scope],
+    )
+
+    main(
+        vmail_root=args.vmail_root,
+        ldap_uri=args.ldap_uri,
+        ldap_starttls=args.ldap_starttls,
+        ldap_bind_dn=args.ldap_bind_dn,
+        ldap_bind_pw=ldap_bind_pw,
+        ldap_base=args.ldap_base,
+        ldap_scope=ldap_scope,
+        ldap_filter=args.ldap_filter,
+        ldap_attr_uuid=args.ldap_attr_uuid,
+        dry_run=not args.execute,
+        verbose=args.verbose,
+    )

migrations/nixos-mailserver-migration-05.py

@@ -0,0 +1,235 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3
+
+import argparse
+import os
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+from pwd import getpwnam
+
+EXIT_OK = 0
+EXIT_ERROR = 1
+
+GREEN = "32"
+YELLOW = "33"
+RED = "31"
+BOLD = "1"
+
+NO_COLOR = "NO_COLOR" in os.environ
+
+
+def color(text, code):
+    if NO_COLOR:
+        return text
+    return f"\033[{code}m{text}\033[0m"
+
+
+def check_user(sieve_root: Path):
+    owner = sieve_root.owner()
+    owner_uid = getpwnam(owner).pw_uid
+
+    if os.geteuid() == owner_uid:
+        return
+
+    try:
+        print(f"Trying to switch effective user id to {owner_uid} ({owner})")
+        os.seteuid(owner_uid)
+        return
+    except PermissionError:
+        print(
+            f"Failed switching to virtual mail user. Please run this script under it, for example by using `sudo -u {owner}`)"
+        )
+    sys.exit(1)
+
+
+def doveadm_get_user_home(user: str) -> Path:
+    output = subprocess.check_output(
+        ["doveadm", "user", "-f", "home", user], text=True, stderr=subprocess.DEVNULL
+    )
+    homedir = Path(output.strip())
+    return homedir
+
+
+def move(src: Path, dst: Path, dry_run: bool = True) -> bool:
+    print(f'mv "{src}" "{dst}"')
+    if not dry_run:
+        try:
+            shutil.move(src, dst)
+        except OSError as exc:
+            print(f"Rename failed ({src=!s}, {dst=!s}): {exc}")
+            return False
+    return True
+
+
+def symlink(target: Path, link: Path, dry_run: bool = True) -> bool:
+    print(f'ln --symbolic --relative "{target}" "{link}"')
+    if not dry_run:
+        try:
+            target_relative = target.relative_to(link.parent)
+            link.symlink_to(target_relative)
+        except (OSError, ValueError) as exc:
+            print(f"Symlinking failed ({target=!s}, {link=!s}): {exc}")
+            return False
+    return True
+
+
+def main(sieve_root: Path, dry_run: bool = True):
+    print(
+        color(
+            f"\nFind accounts based on existing Sieve script directories in {sieve_root!s}",
+            BOLD,
+        )
+    )
+
+    skipped = 0
+    accounts = set()
+    for path in sieve_root.glob("*"):
+        if not path.is_dir():
+            print(f"- Not a directory ({path=!s}) (skipping)")
+            skipped += 1
+            continue
+        elif not set(path.glob("scripts/*.sieve")):
+            print(f"- No Sieve scripts in directory ({path=!s}) (skipping)")
+            skipped += 1
+            continue
+
+        account = path.name
+        accounts.add(account)
+        print(f"- Sieve directory found ({path=!s}, {account=})")
+
+    print(
+        color(
+            f"\nLookup home directory of accounts based on the remaining Sieve directories found in {sieve_root!s}",
+            BOLD,
+        )
+    )
+
+    lookup_failed = 0
+    homedirs = {}
+    for account in accounts:
+        try:
+            homedir = doveadm_get_user_home(account)
+        except subprocess.CalledProcessError as exc:
+            print(f"- Home directory lookup failed ({account=}): {exc}")
+            lookup_failed += 1
+            continue
+        print(f"- Home directory retrieved ({account=}, {homedir=!s})")
+        homedirs.update({account: homedir})
+
+    print(
+        color(
+            "\nEnumerate Sieve directories of accounts",
+            BOLD,
+        )
+    )
+
+    plan = {}
+    for account, homedir in homedirs.items():
+        sieve_src = sieve_root / account / "scripts"
+        sieve_dst = homedir / "sieve"
+        plan.update({sieve_src: sieve_dst})
+
+        active = sieve_root / account / "active.sieve"
+        link = homedir / ".dovecot.sieve"
+        # An account may have Sieve scripts but none enabled,
+        # e.g. an out-of-office auto-reply but currently in-office.
+        if not active.is_symlink():
+            print(
+                f"- Account has Sieve scripts but none enabled ({account=}, {active=!s})"
+            )
+            continue
+        active_relative = active.resolve().relative_to(sieve_src)
+        target = sieve_dst / active_relative
+        plan.update({target: link})
+        print(
+            f"- Account has Sieve scripts and one enabled ({account=}, {sieve_src=!s})"
+        )
+
+    print(color("\nThe following operations will be executed:", BOLD))
+    moved = 0
+    moves_failed = 0
+    for src, dst in plan.items():
+        if src.is_dir():
+            if not move(src=src, dst=dst, dry_run=dry_run):
+                moves_failed += 1
+            else:
+                moved += 1
+        else:
+            if not symlink(target=src, link=dst, dry_run=dry_run):
+                moves_failed += 1
+            else:
+                moved += 1
+
+    print(
+        color(
+            "\nMigration summary",
+            BOLD,
+        )
+    )
+
+    if any([skipped, lookup_failed, not accounts, moves_failed]):
+        print("""
+We strongly recommend reviewing and remediating all potential issues before
+running with `--execute`. Specific details can be found further up.""")
+
+    if moved:
+        print(f"""
+- {color(f"{moved} Sieve script directories were migrated successfully.", GREEN)} {"(dry run)" if dry_run else ""}""")
+
+    if skipped and accounts:
+        print(f"""
+- {color(f"{skipped} paths in {(sieve_root)!s} were skipped.", YELLOW)}
+  These were not a directory or did not contain a ./scripts directory.
+  They should be reviewed but can most likely be deleted.""")
+
+    if lookup_failed:
+        print(f"""
+- {color(f"{lookup_failed} account lookups failed.", YELLOW)}
+  This could be a problem, because we cannot migrate the Sieve script
+  directory into the home directory without finding the owner of the
+  directory. In practice this can happen if an account was deleted but
+  its Sieve script directory remained.""")
+
+    if not accounts:
+        print(f"""
+- {color("No Sieve script directories were found.", RED)}
+  Make sure you are passing the correct `sieve_root` argument. It must match
+  your `mailserver.sieveDirectory` setting. In practise this may also happen
+  if simply no account has Sieve scripts.""")
+
+    if moves_failed:
+        print(f"""
+- {color(f"{moves_failed} Sieve script directories could not be renamed", RED)}
+  No reason to panic, but the script tried to rename a Sieve script directory
+  and that triggered and error. Check further up what went wrong.""")
+
+    if dry_run:
+        print(f"\n{color('No changes were made.', YELLOW)}")
+        print("Run the script with `--execute` to apply the listed changes.")
+
+    sys.exit(EXIT_OK if moves_failed == 0 else EXIT_ERROR)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="""
+        NixOS Mailserver Migration #5: Sieve script directory migration
+        (https://nixos-mailserver.readthedocs.io/en/latest/migrations.html#sieve-script-directory-migration)
+    """
+    )
+    parser.add_argument(
+        "sieve_root", type=Path, help="Path to the `mailserver.sieveDirectory`"
+    )
+    parser.add_argument(
+        "--execute", action="store_true", help="Actually perform changes"
+    )
+
+    args = parser.parse_args()
+
+    check_user(args.sieve_root)
+    main(
+        sieve_root=args.sieve_root,
+        dry_run=not args.execute,
+    )

pyproject.toml

@@ -0,0 +1,5 @@
+[tool.ruff.lint]
+extend-select = ["ISC"]
+
+[tool.ruff.lint.flake8-implicit-str-concat]
+allow-multiline = false

scripts/generate-options.py

@@ -11,12 +11,13 @@ header = """
 """
 
 template = """
+({key})=
 `````{{option}} {key}
-{description}
-
 {type}
 {default}
 {example}
+
+{description}
 `````
 """
 
@@ -24,11 +25,15 @@ f = open(sys.argv[1])
 options = json.load(f)
 
 groups = [
-    "mailserver.loginAccounts",
-    "mailserver.certificate",
+    "mailserver.accounts",
+    "mailserver.x509",
+    "mailserver.storage",
     "mailserver.dkim",
+    "mailserver.srs",
     "mailserver.dmarcReporting",
+    "mailserver.tlsrpt",
     "mailserver.fullTextSearch",
+    "mailserver.quota",
     "mailserver.redis",
     "mailserver.ldap",
     "mailserver.monitoring",
@@ -52,6 +57,8 @@ def render_option_value(option: Mapping[str, Any], key: str) -> str:
     if key not in option:
         return ""
 
+    value = None
+
     if isinstance(option[key], dict) and "_type" in option[key]:
         if option[key]["_type"] == "literalExpression":
             # multi-line codeblock
@@ -75,7 +82,9 @@ def render_option_value(option: Mapping[str, Any], key: str) -> str:
         else:
             value = md_literal(text)
 
-    return f"- {key}: {value}"  # type: ignore
+    assert value is not None
+
+    return f"- {key}: {value}"
 
 
 def print_option(option):
@@ -90,7 +99,9 @@ def print_option(option):
             key=option["name"],
             description=description or "",
             type=f"- type: {md_literal(option['type'])}",
-            default=render_option_value(option, "default"),
+            default=render_option_value(option, "defaultText")
+            if "defaultText" in option
+            else render_option_value(option, "default"),
             example=render_option_value(option, "example"),
         )
     )

scripts/mail-check.py

@@ -12,7 +12,15 @@ RETRY = 100
 
 
 def _send_mail(
-    smtp_host, smtp_port, smtp_username, from_addr, from_pwd, to_addr, subject, starttls
+    smtp_host,
+    smtp_port,
+    smtp_username,
+    from_addr,
+    from_pwd,
+    to_addr,
+    subject,
+    starttls,
+    ssl,
 ):
     print(f"Sending mail with subject '{subject}'")
     message = "\n".join(
@@ -28,9 +36,10 @@ def _send_mail(
     )
 
     retry = RETRY
+    smtp_class = smtplib.SMTP_SSL if ssl else smtplib.SMTP
     while True:
         try:
-            with smtplib.SMTP(smtp_host, port=smtp_port) as smtp:
+            with smtp_class(smtp_host, port=smtp_port) as smtp:
                 try:
                     if starttls:
                         smtp.starttls()
@@ -73,7 +82,7 @@ def _read_mail(
     show_body=False,
     delete=True,
 ):
-    print("Reading mail from {imap_username}")
+    print(f"Reading mail from {imap_username}")
 
     message = None
 
@@ -171,6 +180,7 @@ def send_and_read(args):
         to_addr=args.to_addr,
         subject=subject,
         starttls=args.smtp_starttls,
+        ssl=args.smtp_ssl,
     )
 
     _read_mail(
@@ -206,6 +216,7 @@ parser_send_and_read = subparsers.add_parser(
 parser_send_and_read.add_argument("--smtp-host", type=str)
 parser_send_and_read.add_argument("--smtp-port", type=str, default=25)
 parser_send_and_read.add_argument("--smtp-starttls", action="store_true")
+parser_send_and_read.add_argument("--smtp-ssl", action="store_true")
 parser_send_and_read.add_argument(
     "--smtp-username",
     type=str,

shell.nix

@@ -1,10 +1,9 @@
-(import
-  (
-    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
-    fetchTarball {
-      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-      sha256 = lock.nodes.flake-compat.locked.narHash;
-    }
-  )
-  { src = ./.; }
-).shellNix
+(import (
+  let
+    lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+  in
+  fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+    sha256 = lock.nodes.flake-compat.locked.narHash;
+  }
+) { src = ./.; }).shellNix

tests/clamav.nix

@@ -24,73 +24,79 @@
   name = "clamav";
 
   nodes = {
-    server = { pkgs, ... }:
-        {
-            imports = [
-                ../default.nix
-                ./lib/config.nix
-            ];
+    server =
+      { pkgs, ... }:
+      {
+        imports = [
+          ../default.nix
+          ./lib/config.nix
+        ];
 
-            virtualisation.memorySize = 1500;
+        virtualisation.memorySize = 1500;
 
-            environment.systemPackages = with pkgs; [ netcat ];
+        environment.systemPackages = with pkgs; [ netcat ];
 
-            services.rsyslogd = {
-              enable = true;
-              defaultConfig = ''
-              *.*   /dev/console
-              '';
-            };
-
-            services.clamav.updater.enable = lib.mkForce false;
-            systemd.services.old-clam = {
-              before = [ "clamav-daemon.service" ];
-              requiredBy = [ "clamav-daemon.service" ];
-              description = "ClamAV virus database";
-
-              preStart = ''
-                mkdir -m 0755 -p /var/lib/clamav
-                chown clamav:clamav /var/lib/clamav
-              '';
-
-              script = ''
-                cp ${blobs}/clamav/main.cvd      /var/lib/clamav/
-                cp ${blobs}/clamav/daily.cvd     /var/lib/clamav/
-                cp ${blobs}/clamav/bytecode.cvd  /var/lib/clamav/
-                chown clamav:clamav /var/lib/clamav/*
-              '';
-
-              serviceConfig = {
-                Type = "oneshot";
-                PrivateTmp = "yes";
-                PrivateDevices = "yes";
-              };
-            };
-
-            mailserver = {
-              enable = true;
-              fqdn = "mail.example.com";
-              domains = [ "example.com" "example2.com" ];
-              virusScanning = true;
-
-              loginAccounts = {
-                  "user1@example.com" = {
-                      hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
-                      aliases = [ "postmaster@example.com" ];
-                      catchAll = [ "example.com" ];
-                  };
-                  "user@example2.com" = {
-                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
-                  };
-              };
-              enableImap = true;
-            };
-
-            environment.etc = {
-              "root/eicar.com.txt".text = "X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*";
-            };
+        services.rsyslogd = {
+          enable = true;
+          defaultConfig = ''
+            *.*   /dev/console
+          '';
         };
-      client = { nodes, pkgs, ... }: let
+
+        services.clamav.updater.enable = lib.mkForce false;
+        systemd.services.old-clam = {
+          before = [ "clamav-daemon.service" ];
+          requiredBy = [ "clamav-daemon.service" ];
+          description = "ClamAV virus database";
+
+          preStart = ''
+            mkdir -m 0755 -p /var/lib/clamav
+            chown clamav:clamav /var/lib/clamav
+          '';
+
+          script = ''
+            cp ${blobs}/clamav/main.cvd      /var/lib/clamav/
+            cp ${blobs}/clamav/daily.cvd     /var/lib/clamav/
+            cp ${blobs}/clamav/bytecode.cvd  /var/lib/clamav/
+            chown clamav:clamav /var/lib/clamav/*
+          '';
+
+          serviceConfig = {
+            Type = "oneshot";
+            PrivateTmp = "yes";
+            PrivateDevices = "yes";
+          };
+        };
+
+        mailserver = {
+          enable = true;
+          fqdn = "mail.example.com";
+          domains = [
+            "example.com"
+            "example2.com"
+          ];
+          virusScanning = true;
+
+          accounts = {
+            "user1@example.com" = {
+              hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
+              aliases = [ "postmaster@example.com" ];
+              catchAll = [ "example.com" ];
+            };
+            "user@example2.com" = {
+              hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
+            };
+          };
+          enableImap = true;
+        };
+
+        environment.etc = {
+          "root/eicar.com.txt".text = "X5O!P%@AP[4PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*";
+        };
+      };
+    client =
+      { nodes, pkgs, ... }:
+      let
         serverIP = nodes.server.networking.primaryIPAddress;
         clientIP = nodes.client.networking.primaryIPAddress;
         grep-ip = pkgs.writeScriptBin "grep-ip" ''
@@ -98,20 +104,25 @@
           echo grep '${clientIP}' "$@" >&2
           exec grep '${clientIP}' "$@"
         '';
-      in {
+      in
+      {
         imports = [
-            ./lib/config.nix
+          ./lib/config.nix
         ];
 
         environment.systemPackages = with pkgs; [
-          fetchmail msmtp procmail findutils grep-ip
+          fetchmail
+          msmtp
+          procmail
+          findutils
+          grep-ip
         ];
         environment.etc = {
           "root/.fetchmailrc" = {
             text = ''
-                poll ${serverIP} with proto IMAP
-                user 'user1@example.com' there with password 'user1' is 'root' here
-                mda procmail
+              poll ${serverIP} with proto IMAP
+              user 'user1@example.com' there with password 'user1' is 'root' here
+              mda procmail
             '';
             mode = "0700";
           };
@@ -133,73 +144,74 @@
               password       user2
             '';
           };
-          "root/virus-email".text = ''
-            From: User2 <user@example2.com>
-            Content-Type: multipart/mixed;
-              boundary="Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607"
-            Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\))
-            Subject: Testy McTest
-            Message-Id: <94550DD9-1FF1-4ED1-9F09-8812FF2E59AA@example.com>
-            Date: Sat, 12 May 2018 14:15:44 +0200
-            To: User1 <user1@example.com>
-            X-Mailer: Apple Mail (2.3445.6.18)
+          "root/virus-email".text =
+            # mail
+            ''
+              From: User2 <user@example2.com>
+              Content-Type: multipart/mixed;
+                boundary="Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607"
+              Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\))
+              Subject: Testy McTest
+              Message-Id: <94550DD9-1FF1-4ED1-9F09-8812FF2E59AA@example.com>
+              Date: Sat, 12 May 2018 14:15:44 +0200
+              To: User1 <user1@example.com>
+              X-Mailer: Apple Mail (2.3445.6.18)
 
 
-            --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607
-            Content-Transfer-Encoding: 7bit
-            Content-Type: text/plain;
-              charset=us-ascii
+              --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607
+              Content-Transfer-Encoding: 7bit
+              Content-Type: text/plain;
+                charset=us-ascii
 
-            Hello
+              Hello
 
-            I have attached a dangerous virus.
+              I have attached a dangerous virus.
 
-            Mfg.
-            User2
+              Mfg.
+              User2
 
 
-            --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607
-            Content-Disposition: attachment;
-              filename=eicar.com.txt
-            Content-Type: text/plain;
-              x-unix-mode=0644;
-              name="eicar.com.txt"
-            Content-Transfer-Encoding: 7bit
+              --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607
+              Content-Disposition: attachment;
+                filename=eicar.com.txt
+              Content-Type: text/plain;
+                x-unix-mode=0644;
+                name="eicar.com.txt"
+              Content-Transfer-Encoding: 7bit
 
-            X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
-            --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607--
-          '';
-          "root/safe-email".text = ''
-            From: User <user@example2.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user@example2.com to user1
-            Reply-To:
+              X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*
+              --Apple-Mail=_2689C63E-FD18-4E4D-8822-54797BDA9607--
+            '';
+          "root/safe-email".text =
+            # mail
+            ''
+              From: User <user@example2.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user@example2.com to user1
+              Reply-To:
 
-            Hello User1,
+              Hello User1,
 
-            how are you doing today?
+              how are you doing today?
 
-            XOXO User1
-          '';
+              XOXO User1
+            '';
         };
       };
-    };
+  };
 
-  testScript = ''
+  testScript =
+    # python
+    ''
       start_all()
 
       server.wait_for_unit("multi-user.target")
       client.wait_for_unit("multi-user.target")
 
-      # TODO put this blocking into the systemd units? I am not sure if rspamd already waits for the clamd socket.
-      server.wait_until_succeeds(
-          "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
-      )
-      server.wait_until_succeeds(
-          "set +e; timeout 1 nc -U /run/clamav/clamd.ctl < /dev/null; [ $? -eq 124 ]"
-      )
+      server.wait_for_open_unix_socket("/run/rspamd/rspamd-milter.sock")
+      server.wait_for_open_unix_socket("/run/clamav/clamd.ctl")
 
       client.execute("cp -p /etc/root/.* ~/")
       client.succeed("mkdir -p ~/mail")
@@ -237,7 +249,7 @@
       with subtest("no warnings or errors"):
           server.fail("journalctl -u postfix | grep -i error >&2")
           server.fail("journalctl -u postfix | grep -i warning >&2")
-          server.fail("journalctl -u dovecot2 | grep -i error >&2")
-          server.fail("journalctl -u dovecot2 | grep -i warning >&2")
+          server.fail("journalctl -u dovecot | grep -i error >&2")
+          server.fail("journalctl -u dovecot | grep -i warning >&2")
     '';
 }

tests/external.nix

@@ -18,74 +18,97 @@
   name = "external";
 
   nodes = {
-    server = { pkgs, ... }:
-        {
-            imports = [
-                ../default.nix
-                ./lib/config.nix
-            ];
+    server =
+      { pkgs, ... }:
+      {
+        imports = [
+          ../default.nix
+          ./lib/config.nix
+        ];
 
-            environment.systemPackages = with pkgs; [ netcat ];
+        environment.systemPackages = with pkgs; [
+          netcat
+          openssl
+        ];
 
-            virtualisation.memorySize = 1024;
+        virtualisation.memorySize = 1024;
 
-            services.rsyslogd = {
-              enable = true;
-              defaultConfig = ''
-              *.*   /dev/console
-              '';
-            };
-
-
-            mailserver = {
-              enable = true;
-              debug = true;
-              fqdn = "mail.example.com";
-              domains = [ "example.com" "example2.com" ];
-              rewriteMessageId = true;
-              dkimKeyBits = 1535;
-              dmarcReporting = {
-                enable = true;
-                domain = "example.com";
-                organizationName = "ACME Corp";
-              };
-
-              loginAccounts = {
-                  "user1@example.com" = {
-                      hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
-                      aliases = [ "postmaster@example.com" ];
-                      catchAll = [ "example.com" ];
-                  };
-                  "user2@example.com" = {
-                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
-                      aliases = [ "chuck@example.com" ];
-                  };
-                  "user@example2.com" = {
-                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
-                  };
-                  "lowquota@example.com" = {
-                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
-                      quota = "1B";
-                  };
-              };
-
-              extraVirtualAliases = {
-                "single-alias@example.com" = "user1@example.com";
-                "multi-alias@example.com" = [ "user1@example.com" "user2@example.com" ];
-              };
-
-              enableImap = true;
-              enableImapSsl = true;
-              fullTextSearch = {
-                enable = true;
-                autoIndex = true;
-                # special use depends on https://github.com/NixOS/nixpkgs/pull/93201
-                autoIndexExclude = [ (if (pkgs.lib.versionAtLeast pkgs.lib.version "21") then "\\Junk" else "Junk") ];
-                enforced = "yes";
-              };
-            };
+        services.rsyslogd = {
+          enable = true;
+          defaultConfig = ''
+            *.*   /dev/console
+          '';
         };
-      client = { nodes, pkgs, ... }: let
+
+        mailserver = {
+          enable = true;
+          debug.dovecot = true; # enabled for sieve script logging
+          fqdn = "mail.example.com";
+          domains = [
+            "example.com"
+            "example2.com"
+          ];
+          rewriteMessageId = true;
+          dkim = {
+            defaults.keyLength = 1535;
+            domains."example2.com".selectors = {
+              "dkim-rsa" = {
+                # rsa 1535 bits via defaults
+              };
+              "dkim-ed25519" = {
+                keyType = "ed25519";
+                keyLength = null;
+              };
+              "dkim-file" = {
+                keyFile = "/run/rspamd/dkim-test.key";
+              };
+            };
+          };
+          dmarcReporting.enable = true;
+
+          accounts = {
+            "user1@example.com" = {
+              hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
+              aliases = [ "postmaster@example.com" ];
+              catchAll = [ "example.com" ];
+            };
+            "user2@example.com" = {
+              hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
+              aliases = [ "chuck@example.com" ];
+            };
+            "user@example2.com" = {
+              hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
+            };
+            "lowquota@example.com" = {
+              hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
+              quota = "1K";
+            };
+          };
+
+          aliases = {
+            "single-alias@example.com" = "user1@example.com";
+            "multi-alias@example.com" = [
+              "user1@example.com"
+              "user2@example.com"
+            ];
+          };
+
+          enableImap = true;
+          enableImapSsl = true;
+          fullTextSearch = {
+            enable = true;
+            autoIndex = true;
+            fallback = false;
+          };
+        };
+
+        # by default quota can be exceeded once with this amount (default: 10M)
+        # this is required to make the quota subtest hard fail on the first attempt.
+        services.dovecot2.settings.quota_storage_grace = "0";
+      };
+    client =
+      { nodes, pkgs, ... }:
+      let
         serverIP = nodes.server.networking.primaryIPAddress;
         clientIP = nodes.client.networking.primaryIPAddress;
         grep-ip = pkgs.writeScriptBin "grep-ip" ''
@@ -98,101 +121,119 @@
           echo grep '^Message-ID:.*@mail.example.com>$' "$@" >&2
           exec grep '^Message-ID:.*@mail.example.com>$' "$@"
         '';
-        test-imap-spam = pkgs.writeScriptBin "imap-mark-spam" ''
-          #!${pkgs.python3.interpreter}
-          import imaplib
+        test-imap-spam =
+          pkgs.writeScriptBin "imap-mark-spam"
+            # python
+            ''
+              #!${pkgs.python3.interpreter}
+              import imaplib
 
-          with imaplib.IMAP4_SSL('${serverIP}') as imap:
-            imap.login('user1@example.com', 'user1')
-            imap.select()
-            status, [response] = imap.search(None, 'ALL')
-            msg_ids = response.decode("utf-8").split(' ')
-            print(msg_ids)
-            assert status == 'OK'
-            assert len(msg_ids) == 1
+              with imaplib.IMAP4_SSL('${serverIP}') as imap:
+                imap.login('user1@example.com', 'user1')
+                imap.select()
+                status, [response] = imap.search(None, 'ALL')
+                msg_ids = response.decode("utf-8").split(' ')
+                print(msg_ids)
+                assert status == 'OK'
+                assert len(msg_ids) == 1
 
-            imap.copy(','.join(msg_ids), 'Junk')
-            for num in msg_ids:
-              imap.store(num, '+FLAGS', '\\Deleted')
-            imap.expunge()
+                imap.copy(','.join(msg_ids), 'Junk')
+                for num in msg_ids:
+                  imap.store(num, '+FLAGS', '\\Deleted')
+                imap.expunge()
 
-            imap.select('Junk')
-            status, [response] = imap.search(None, 'ALL')
-            msg_ids = response.decode("utf-8").split(' ')
-            print(msg_ids)
-            assert status == 'OK'
-            assert len(msg_ids) == 1
+                imap.select('Junk')
+                status, [response] = imap.search(None, 'ALL')
+                msg_ids = response.decode("utf-8").split(' ')
+                print(msg_ids)
+                assert status == 'OK'
+                assert len(msg_ids) == 1
 
-            imap.close()
-        '';
-        test-imap-ham = pkgs.writeScriptBin "imap-mark-ham" ''
-          #!${pkgs.python3.interpreter}
-          import imaplib
+                imap.close()
+            '';
+        test-imap-ham =
+          pkgs.writeScriptBin "imap-mark-ham"
+            # python
+            ''
+              #!${pkgs.python3.interpreter}
+              import imaplib
 
-          with imaplib.IMAP4_SSL('${serverIP}') as imap:
-            imap.login('user1@example.com', 'user1')
-            imap.select('Junk')
-            status, [response] = imap.search(None, 'ALL')
-            msg_ids = response.decode("utf-8").split(' ')
-            print(msg_ids)
-            assert status == 'OK'
-            assert len(msg_ids) == 1
+              with imaplib.IMAP4_SSL('${serverIP}') as imap:
+                imap.login('user1@example.com', 'user1')
+                imap.select('Junk')
+                status, [response] = imap.search(None, 'ALL')
+                msg_ids = response.decode("utf-8").split(' ')
+                print(msg_ids)
+                assert status == 'OK'
+                assert len(msg_ids) == 1
 
-            imap.copy(','.join(msg_ids), 'INBOX')
-            for num in msg_ids:
-              imap.store(num, '+FLAGS', '\\Deleted')
-            imap.expunge()
+                imap.copy(','.join(msg_ids), 'INBOX')
+                for num in msg_ids:
+                  imap.store(num, '+FLAGS', '\\Deleted')
+                imap.expunge()
 
-            imap.select('INBOX')
-            status, [response] = imap.search(None, 'ALL')
-            msg_ids = response.decode("utf-8").split(' ')
-            print(msg_ids)
-            assert status == 'OK'
-            assert len(msg_ids) == 1
+                imap.select('INBOX')
+                status, [response] = imap.search(None, 'ALL')
+                msg_ids = response.decode("utf-8").split(' ')
+                print(msg_ids)
+                assert status == 'OK'
+                assert len(msg_ids) == 1
 
-            imap.close()
-        '';
-        search = pkgs.writeScriptBin "search" ''
-          #!${pkgs.python3.interpreter}
-          import imaplib
-          import sys
+                imap.close()
+            '';
+        search =
+          pkgs.writeScriptBin "search"
+            # python
+            ''
+              #!${pkgs.python3.interpreter}
+              import imaplib
+              import sys
 
-          [_, mailbox, needle] = sys.argv
+              [_, mailbox, needle] = sys.argv
 
-          with imaplib.IMAP4_SSL('${serverIP}') as imap:
-            imap.login('user1@example.com', 'user1')
-            imap.select(mailbox)
-            status, [response] = imap.search(None, 'BODY', repr(needle))
-            msg_ids = [ i for i in response.decode("utf-8").split(' ') if i ]
-            print(msg_ids)
-            assert status == 'OK'
-            assert len(msg_ids) == 1
-            status, response = imap.fetch(msg_ids[0], '(RFC822)')
-            assert status == "OK"
-            assert needle in repr(response)
-            imap.close()
-        '';
-      in {
+              with imaplib.IMAP4_SSL('${serverIP}') as imap:
+                imap.login('user1@example.com', 'user1')
+                imap.select(mailbox)
+                status, [response] = imap.search(None, 'BODY', repr(needle))
+                msg_ids = [ i for i in response.decode("utf-8").split(' ') if i ]
+                print(msg_ids)
+                assert status == 'OK'
+                assert len(msg_ids) == 1
+                status, response = imap.fetch(msg_ids[0], '(RFC822)')
+                assert status == "OK"
+                assert needle in repr(response)
+                imap.close()
+            '';
+      in
+      {
         imports = [
-            ./lib/config.nix
+          ./lib/config.nix
         ];
         environment.systemPackages = with pkgs; [
-          fetchmail msmtp procmail findutils grep-ip check-mail-id test-imap-spam test-imap-ham search
+          fetchmail
+          msmtp
+          procmail
+          findutils
+          grep-ip
+          check-mail-id
+          test-imap-spam
+          test-imap-ham
+          search
         ];
         environment.etc = {
           "root/.fetchmailrc" = {
             text = ''
-                poll ${serverIP} with proto IMAP
-                user 'user1@example.com' there with password 'user1' is 'root' here
-                mda procmail
+              poll ${serverIP} with proto IMAP
+              user 'user1@example.com' there with password 'user1' is 'root' here
+              mda procmail
             '';
             mode = "0700";
           };
           "root/.fetchmailRcLowQuota" = {
             text = ''
-                poll ${serverIP} with proto IMAP
-                user 'lowquota@example.com' there with password 'user2' is 'root' here
-                mda procmail
+              poll ${serverIP} with proto IMAP
+              user 'lowquota@example.com' there with password 'user2' is 'root' here
+              mda procmail
             '';
             mode = "0700";
           };
@@ -237,119 +278,149 @@
               password       user1
             '';
           };
-          "root/email1".text = ''
-            Message-ID: <12345qwerty@host.local.network>
-            From: User2 <user2@example.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user2 to user1
-            Reply-To:
+          "root/email1".text =
+            # mail
+            ''
+              Message-ID: <12345qwerty@host.local.network>
+              From: User2 <user2@example.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user2 to user1
+              Reply-To:
 
-            Hello User1,
+              Hello User1,
 
-            how are you doing today?
-          '';
-          "root/email2".text = ''
-            Message-ID: <232323abc@host.local.network>
-            From: User <user@example2.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user@example2.com to user1
-            Reply-To:
+              how are you doing today?
+            '';
+          "root/email2".text =
+            # mail
+            ''
+              Message-ID: <232323abc@host.local.network>
+              From: User <user@example2.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user@example2.com to user1
+              Reply-To:
 
-            Hello User1,
+              Hello User1,
 
-            how are you doing today?
+              how are you doing today? I have this exciting text for you, that helps fill
+              your quota.
 
-            XOXO User1
-          '';
-          "root/email3".text = ''
-            Message-ID: <asdfghjkl42@host.local.network>
-            From: Postmaster <postmaster@example.com>
-            To: Chuck <chuck@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from postmaster@example.com to chuck
-            Reply-To:
+              Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod
+              tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At
+              vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren,
+              no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit
+              amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut
+              labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam
+              et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata
+              sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur
+              sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore
+              magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo
+              dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est
+              Lorem ipsum dolor sit amet.
 
-            Hello Chuck,
+              XOXO User1
+            '';
+          "root/email3".text =
+            # mail
+            ''
+              Message-ID: <asdfghjkl42@host.local.network>
+              From: Postmaster <postmaster@example.com>
+              To: Chuck <chuck@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from postmaster@example.com to chuck
+              Reply-To:
 
-            I think I may have misconfigured the mail server
-            XOXO Postmaster
-          '';
-          "root/email4".text = ''
-            Message-ID: <sdfsdf@host.local.network>
-            From: Single Alias <single-alias@example.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from single-alias@example.com to user1
-            Reply-To:
+              Hello Chuck,
 
-            Hello User1,
+              I think I may have misconfigured the mail server
+              XOXO Postmaster
+            '';
+          "root/email4".text =
+            # mail
+            ''
+              Message-ID: <sdfsdf@host.local.network>
+              From: Single Alias <single-alias@example.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from single-alias@example.com to user1
+              Reply-To:
 
-            how are you doing today?
+              Hello User1,
 
-            XOXO User1 aka Single Alias
-          '';
-          "root/email5".text = ''
-            Message-ID: <789asdf@host.local.network>
-            From: User2 <user2@example.com>
-            To: Multi Alias <multi-alias@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user2@example.com to multi-alias
-            Reply-To:
+              how are you doing today?
 
-            Hello Multi Alias,
+              XOXO User1 aka Single Alias
+            '';
+          "root/email5".text =
+            # mail
+            ''
+              Message-ID: <789asdf@host.local.network>
+              From: User2 <user2@example.com>
+              To: Multi Alias <multi-alias@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user2@example.com to multi-alias
+              Reply-To:
 
-            how are we doing today?
+              Hello Multi Alias,
 
-            XOXO User1
-          '';
-          "root/email6".text = ''
-            Message-ID: <123457qwerty@host.local.network>
-            From: User2 <user2@example.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user2 to user1
-            Reply-To:
+              how are we doing today?
 
-            Hello User1,
+              XOXO User1
+            '';
+          "root/email6".text =
+            # mail
+            ''
+              Message-ID: <123457qwerty@host.local.network>
+              From: User2 <user2@example.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user2 to user1
+              Reply-To:
 
-            this email contains the needle:
-            576a4565b70f5a4c1a0925cabdb587a6
-          '';
-          "root/email7".text = ''
-            Message-ID: <1234578qwerty@host.local.network>
-            From: User2 <user2@example.com>
-            To: User1 <user1@example.com>
-            Cc:
-            Bcc:
-            Subject: This is a test Email from user2 to user1
-            Reply-To:
+              Hello User1,
 
-            Hello User1,
+              this email contains the needle:
+              576a4565b70f5a4c1a0925cabdb587a6
+            '';
+          "root/email7".text =
+            # mail
+            ''
+              Message-ID: <1234578qwerty@host.local.network>
+              From: User2 <user2@example.com>
+              To: User1 <user1@example.com>
+              Cc:
+              Bcc:
+              Subject: This is a test Email from user2 to user1
+              Reply-To:
 
-            this email does not contain the needle :(
-          '';
+              Hello User1,
+
+              this email does not contain the needle :(
+            '';
         };
       };
-    };
+  };
 
-  testScript = ''
+  testScript =
+    # python
+    ''
       start_all()
 
       server.wait_for_unit("multi-user.target")
       client.wait_for_unit("multi-user.target")
 
-      # TODO put this blocking into the systemd units?
-      server.wait_until_succeeds(
-          "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
-      )
+      server.wait_for_open_unix_socket("/run/rspamd/rspamd-milter.sock")
+
+      server.succeed("rspamadm dkim_keygen > /run/rspamd/dkim-test.key")
+      server.succeed("chown rspamd: /run/rspamd/dkim-test.key")
 
       client.execute("cp -p /etc/root/.* ~/")
       client.succeed("mkdir -p ~/mail")
@@ -386,10 +457,10 @@
 
       with subtest("dkim has user-specified size"):
           server.succeed(
-              "openssl rsa -in /var/dkim/example.com.mail.key -text -noout | grep 'Private-Key: (1535 bit'"
+              "openssl rsa -in /var/dkim/example2.com.dkim-rsa.key -text -noout | grep 'Private-Key: (1535 bit'"
           )
 
-      with subtest("dkim singing, multiple domains"):
+      with subtest("dkim signing, multiple domains"):
           client.execute("rm ~/mail/*")
           # send email from user2 to user1
           client.succeed(
@@ -400,7 +471,9 @@
           client.succeed("fetchmail  --nosslcertck -v")
           client.succeed("cat ~/mail/* >&2")
           # make sure it is dkim signed
-          client.succeed("grep DKIM-Signature: ~/mail/*")
+          client.succeed("grep 's=dkim-rsa' ~/mail/*")
+          client.succeed("grep 's=dkim-ed25519' ~/mail/*")
+          client.succeed("grep 's=dkim-file' ~/mail/*")
 
       with subtest("aliases"):
           client.execute("rm ~/mail/*")
@@ -412,9 +485,9 @@
           # fetchmail returns EXIT_CODE 0 when it retrieves mail
           client.succeed("fetchmail --nosslcertck -v")
 
-      with subtest("catchAlls"):
+      with subtest("domain catch-all"):
           client.execute("rm ~/mail/*")
-          # send email from chuck to non exsitent account
+          # send email from chuck to non-existent account
           client.succeed(
               "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lol@example.com < /etc/root/email2 >&2"
           )
@@ -429,10 +502,10 @@
           )
           server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
           # fetchmail returns EXIT_CODE 1 when no new mail
-          # if this succeeds, it means that user1 recieved the mail that was intended for chuck.
+          # if this succeeds, it means that user1 received the mail that was intended for chuck.
           client.fail("fetchmail --nosslcertck -v")
 
-      with subtest("extraVirtualAliases"):
+      with subtest("Test sending from alias address (mailserver.aliases)"):
           client.execute("rm ~/mail/*")
           # send email from single-alias to user1
           client.succeed(
@@ -455,6 +528,8 @@
           client.execute("rm ~/mail/*")
           client.execute("mv ~/.fetchmailRcLowQuota ~/.fetchmailrc")
 
+          server.log(server.succeed("doveadm quota get -u lowquota@example.com"))
+
           client.succeed(
               "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lowquota@example.com < /etc/root/email2 >&2"
           )
@@ -471,9 +546,9 @@
           server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
 
           client.succeed("imap-mark-spam >&2")
-          server.wait_until_succeeds("journalctl -u dovecot2 | grep -i rspamd-learn-spam.sh >&2")
+          server.wait_until_succeeds("journalctl -u dovecot | grep -i rspamd-learn-spam.sh >&2")
           client.succeed("imap-mark-ham >&2")
-          server.wait_until_succeeds("journalctl -u dovecot2 | grep -i rspamd-learn-ham.sh >&2")
+          server.wait_until_succeeds("journalctl -u dovecot | grep -i rspamd-learn-ham.sh >&2")
 
       with subtest("full text search and indexation"):
           # send 2 email from user2 to user1
@@ -491,9 +566,9 @@
           # should fail because this folder is not indexed
           client.fail("search Junk a >&2")
           # check that search really goes through the indexer
-          server.succeed("journalctl -u dovecot2 | grep 'fts-flatcurve(INBOX): Query ' >&2")
+          server.succeed("journalctl -u dovecot | grep 'fts-flatcurve(INBOX): Query ' >&2")
           # check that Junk is not indexed
-          server.fail("journalctl -u dovecot2 | grep 'fts-flatcurve(JUNK): Indexing ' >&2")
+          server.fail("journalctl -u dovecot | grep 'fts-flatcurve(JUNK): Indexing ' >&2")
 
       with subtest("dmarc reporting"):
           server.systemctl("start rspamd-dmarc-reporter.service")
@@ -501,10 +576,10 @@
       with subtest("no warnings or errors"):
           server.fail("journalctl -u postfix | grep -i error >&2")
           server.fail("journalctl -u postfix | grep -i warning >&2")
-          server.fail("journalctl -u dovecot2 | grep -v 'imap-login: Debug: SSL error: Connection closed' | grep -i error >&2")
+          server.fail("journalctl -u dovecot | grep -v 'imap-login: Debug: SSL error: Connection closed' | grep -i error >&2")
           # harmless ? https://dovecot.org/pipermail/dovecot/2020-August/119575.html
           server.fail(
-            "journalctl -u dovecot2 | \
+            "journalctl -u dovecot | \
               grep -v 'Expunged message reappeared, giving a new UID' | \
               grep -v 'Time moved forwards' | \
               grep -i warning >&2"

tests/internal.nix

@@ -30,175 +30,295 @@ let
     '';
   };
 
-  hashPassword = password: pkgs.runCommand
-    "password-${password}-hashed"
-    { buildInputs = [ pkgs.mkpasswd ]; inherit password; } ''
-      mkpasswd -sm bcrypt <<<"$password" > $out
-    '';
+  hashPassword =
+    password:
+    pkgs.runCommand "password-${password}-hashed"
+      {
+        buildInputs = [ pkgs.mkpasswd ];
+        inherit password;
+      }
+      ''
+        mkpasswd -s <<<"$password" > $out
+      '';
+
+  hashPasswordWithScheme =
+    password:
+    pkgs.runCommand "password-${password}-hashed-with-scheme"
+      {
+        buildInputs = [ pkgs.dovecot ];
+        inherit password;
+      }
+      ''
+        printf "$password\n$password\n" | doveadm -O pw -s SSHA256 > $out
+      '';
 
   hashedPasswordFile = hashPassword "my-password";
+  hashedPasswordFileWithScheme = hashPasswordWithScheme "my-password";
   passwordFile = pkgs.writeText "password" "my-password";
 in
 {
   name = "internal";
 
   nodes = {
-    machine = { pkgs, ... }: {
-      imports = [
-        ./../default.nix
-        ./lib/config.nix
-      ];
+    machine =
+      { pkgs, lib, ... }:
+      {
+        imports = [
+          ./../default.nix
+          ./lib/config.nix
+        ];
 
-      virtualisation.memorySize = 1024;
+        virtualisation.memorySize = 1024;
 
-      environment.systemPackages = [
-        (pkgs.writeScriptBin "mail-check" ''
-          ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
-        '')
-      ] ++ (with pkgs; [
-        curl
-        openssl
-        netcat
-      ]);
+        environment.systemPackages = [
+          (pkgs.writeScriptBin "mail-check" ''
+            ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
+          '')
+        ]
+        ++ (with pkgs; [
+          curl
+          openssl
+          netcat
+        ]);
 
-      mailserver = {
-        enable = true;
-        fqdn = "mail.example.com";
-        domains = [ "example.com" "domain.com" ];
-        localDnsResolver = false;
-
-        loginAccounts = {
-          "user1@example.com" = {
-            hashedPasswordFile = hashedPasswordFile;
-          };
-          "user2@example.com" = {
-            hashedPasswordFile = hashedPasswordFile;
-            aliasesRegexp = [''/^user2.*@domain\.com$/''];
-          };
-          "send-only@example.com" = {
-            hashedPasswordFile = hashPassword "send-only";
-            sendOnly = true;
+        systemd.tmpfiles.settings."mailserver-test-passwords" = {
+          "/run/passwords/user3" = {
+            f = {
+              argument = "my-password";
+              mode = "0600";
+            };
           };
         };
-        forwards = {
-          # user2@example.com is a local account and its mails are
-          # also forwarded to user1@example.com
-          "user2@example.com" = "user1@example.com";
+
+        systemd.services.dovecot.serviceConfig.CacheDirectory = "dovecot";
+
+        mailserver = {
+          enable = true;
+          fqdn = "mail.example.com";
+          domains = [
+            "example.com"
+            "domain.com"
+          ];
+          localDnsResolver = false;
+
+          accounts = {
+            "user1@example.com" = {
+              hashedPasswordFile = hashedPasswordFile;
+            };
+            "user2@example.com" = {
+              hashedPasswordFile = hashedPasswordFile;
+              aliasesRegexp = [ ''/^user2.*@domain\.com$/'' ];
+            };
+            "user3@example.com" = {
+              passwordFile = "/run/passwords/user3";
+              sieveScript = lib.readFile ./lib/redirect.sieve;
+            };
+            "user4@example.com" = {
+              hashedPasswordFile = hashedPasswordFileWithScheme;
+            };
+            "send-only@example.com" = {
+              hashedPasswordFile = hashPassword "send-only";
+              sendOnly = true;
+            };
+          };
+          forwards = {
+            # user2@example.com is a local account and its mails are
+            # also forwarded to user1@example.com
+            "user2@example.com" = "user1@example.com";
+          };
+
+          storage = {
+            gid = 5000;
+            group = "vmail";
+          };
+
+          indexDir = "/var/cache/dovecot/fts";
+
+          enableImap = false;
         };
-
-        vmailGroupName = "vmail";
-        vmailUID = 5000;
-
-        enableImap = false;
       };
-    };
   };
-  testScript = ''
-    machine.start()
-    machine.wait_for_unit("multi-user.target")
+  testScript =
+    {
+      nodes,
+      ...
+    }:
+    # python
+    ''
+      machine.start()
+      machine.wait_for_unit("multi-user.target")
+      machine.wait_for_unit("dovecot.service")
 
-    # Regression test for https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/issues/205
-    with subtest("mail forwarded can are locally kept"):
-        # A mail sent to user2@example.com is in the user1@example.com mailbox
-        machine.succeed(
-            " ".join(
-                [
-                    "mail-check send-and-read",
-                    "--smtp-port 587",
-                    "--smtp-starttls",
-                    "--smtp-host localhost",
-                    "--imap-host localhost",
-                    "--imap-username user1@example.com",
-                    "--from-addr user1@example.com",
-                    "--to-addr user2@example.com",
-                    "--src-password-file ${passwordFile}",
-                    "--dst-password-file ${passwordFile}",
-                    "--ignore-dkim-spf",
-                ]
-            )
-        )
-        # A mail sent to user2@example.com is in the user2@example.com mailbox
-        machine.succeed(
-            " ".join(
-                [
-                    "mail-check send-and-read",
-                    "--smtp-port 587",
-                    "--smtp-starttls",
-                    "--smtp-host localhost",
-                    "--imap-host localhost",
-                    "--imap-username user2@example.com",
-                    "--from-addr user1@example.com",
-                    "--to-addr user2@example.com",
-                    "--src-password-file ${passwordFile}",
-                    "--dst-password-file ${passwordFile}",
-                    "--ignore-dkim-spf",
-                ]
-            )
-        )
+      machine.wait_for_open_unix_socket("/run/rspamd/rspamd-milter.sock")
 
-    with subtest("regex email alias are received"):
-        # A mail sent to user2-regex-alias@domain.com is in the user2@example.com mailbox
-        machine.succeed(
-            " ".join(
-                [
-                    "mail-check send-and-read",
-                    "--smtp-port 587",
-                    "--smtp-starttls",
-                    "--smtp-host localhost",
-                    "--imap-host localhost",
-                    "--imap-username user2@example.com",
-                    "--from-addr user1@example.com",
-                    "--to-addr user2-regex-alias@domain.com",
-                    "--src-password-file ${passwordFile}",
-                    "--dst-password-file ${passwordFile}",
-                    "--ignore-dkim-spf",
-                ]
-            )
-        )
+      # Regression test for https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/issues/205
+      with subtest("mail forwarded can are locally kept"):
+          # A mail sent to user2@example.com via explicit TLS is in the user1@example.com mailbox
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 587",
+                      "--smtp-starttls",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user1@example.com",
+                      "--from-addr user1@example.com",
+                      "--to-addr user2@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
+          # A mail sent to user2@example.com via implicit TLS is in the user2@example.com mailbox
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 465",
+                      "--smtp-ssl",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user2@example.com",
+                      "--from-addr user1@example.com",
+                      "--to-addr user2@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
 
-    with subtest("user can send from regex email alias"):
-        # A mail sent from user2-regex-alias@domain.com, using user2@example.com credentials is received
-        machine.succeed(
-            " ".join(
-                [
-                    "mail-check send-and-read",
-                    "--smtp-port 587",
-                    "--smtp-starttls",
-                    "--smtp-host localhost",
-                    "--imap-host localhost",
-                    "--smtp-username user2@example.com",
-                    "--from-addr user2-regex-alias@domain.com",
-                    "--to-addr user1@example.com",
-                    "--src-password-file ${passwordFile}",
-                    "--dst-password-file ${passwordFile}",
-                    "--ignore-dkim-spf",
-                ]
-            )
-        )
+      with subtest("regex email alias are received"):
+          # A mail sent to user2-regex-alias@domain.com via explicit TLS is in the user2@example.com mailbox
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 587",
+                      "--smtp-starttls",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user2@example.com",
+                      "--from-addr user1@example.com",
+                      "--to-addr user2-regex-alias@domain.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
 
-    with subtest("vmail gid is set correctly"):
-        machine.succeed("getent group vmail | grep 5000")
+      with subtest("user can send from regex email alias"):
+          # A mail sent to user1@example.com from user2-regex-alias@domain.com by
+          # user2@example.com via implicit TLS is in the user1@example.com mailbox
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 465",
+                      "--smtp-ssl",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--smtp-username user2@example.com",
+                      "--from-addr user2-regex-alias@domain.com",
+                      "--to-addr user1@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
 
-    with subtest("mail to send only accounts is rejected"):
-        machine.wait_for_open_port(25)
-        # TODO put this blocking into the systemd units
-        machine.wait_until_succeeds(
-            "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
-        )
-        machine.succeed(
-            "cat ${sendMail} | nc localhost 25 | grep -q '554 5.5.0 Error'"
-        )
+      with subtest("vmail gid is set correctly"):
+          machine.succeed("getent group vmail | grep 5000")
 
-    with subtest("rspamd controller serves web ui"):
-        machine.succeed(
-            "set +o pipefail; curl --unix-socket /run/rspamd/worker-controller.sock http://localhost/ | grep -q '<body>'"
-        )
+      with subtest("Check dovecot maildir and index locations"):
+          # If these paths change we need a migration
+          machine.succeed("doveadm user -f home user1@example.com | grep ${nodes.machine.mailserver.storage.path}/example.com/user1")
+          machine.succeed("doveadm user -f mail_path user1@example.com | grep ${nodes.machine.mailserver.storage.path}/example.com/user1/mail")
+          machine.succeed("doveadm user -f mail_index_path user1@example.com | grep ${nodes.machine.mailserver.indexDir}/example.com/user1")
 
-    with subtest("imap port 143 is closed and imaps is serving SSL"):
-        machine.wait_for_closed_port(143)
-        machine.wait_for_open_port(993)
-        machine.succeed(
-            "echo | openssl s_client -connect localhost:993 | grep 'New, TLS'"
-        )
-  '';
+      with subtest("mail to send only accounts is rejected"):
+          machine.wait_for_open_port(25)
+          # TODO put this blocking into the systemd units
+          machine.wait_until_succeeds(
+              "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
+          )
+          machine.succeed(
+              "cat ${sendMail} | nc localhost 25 | grep -q '554 5.5.0 Error'"
+          )
+
+      with subtest("rspamd controller serves web ui"):
+          machine.succeed(
+              "set +o pipefail; curl --unix-socket /run/rspamd/worker-controller.sock http://localhost/ | grep -q '<body>'"
+          )
+
+      with subtest("user with plaintext password file can send and receive"):
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 587",
+                      "--smtp-starttls",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user3@example.com",
+                      "--from-addr user3@example.com",
+                      "--to-addr user3@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
+
+      with subtest("user with scheme-prefixed hashedPasswordFile can send and receive"):
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 587",
+                      "--smtp-starttls",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user4@example.com",
+                      "--from-addr user4@example.com",
+                      "--to-addr user4@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
+
+      with subtest("user's static Sieve script is being executed"):
+          # user3@example.com has a cfg.sieveScript that forwards every
+          # mail sent from user1@example.com back to user1@example.com
+          machine.succeed(
+              " ".join(
+                  [
+                      "mail-check send-and-read",
+                      "--smtp-port 587",
+                      "--smtp-starttls",
+                      "--smtp-host localhost",
+                      "--imap-host localhost",
+                      "--imap-username user1@example.com",
+                      "--from-addr user1@example.com",
+                      "--to-addr user3@example.com",
+                      "--src-password-file ${passwordFile}",
+                      "--dst-password-file ${passwordFile}",
+                      "--ignore-dkim-spf",
+                  ]
+              )
+          )
+
+      with subtest("imap port 143 is closed and imaps is serving SSL"):
+          machine.wait_for_closed_port(143)
+          machine.wait_for_open_port(993)
+          machine.succeed(
+              "echo | openssl s_client -connect localhost:993 | grep 'New, TLS'"
+          )
+    '';
 }

tests/ldap.nix

@@ -1,218 +1,379 @@
+{
+  pkgs,
+  ...
+}:
 let
+  hashPassword =
+    password:
+    pkgs.runCommand "password-${password}-hashed"
+      {
+        buildInputs = [ pkgs.mkpasswd ];
+        inherit password;
+      }
+      ''
+        mkpasswd -s <<<"$password" > $out
+      '';
+
   bindPassword = "unsafegibberish";
   alicePassword = "testalice";
   bobPassword = "testbob";
+  carolPassword = "testcarol";
+  malloryPassword = "testmallory";
 in
 {
   name = "ldap";
 
   nodes = {
-    machine = { pkgs, ... }: {
-      imports = [
-        ./../default.nix
-        ./lib/config.nix
-      ];
+    machine =
+      { pkgs, lib, ... }:
+      {
+        imports = [
+          ../default.nix
+          ./lib/config.nix
+        ];
 
-      virtualisation.memorySize = 1024;
+        environment.systemPackages = [
+          (pkgs.writeScriptBin "mail-check" ''
+            ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
+          '')
+        ];
 
-      services.openssh = {
-        enable = true;
-        settings.PermitRootLogin = "yes";
-      };
+        environment.etc.bind-password.text = bindPassword;
 
-      environment.systemPackages = [
-        (pkgs.writeScriptBin "mail-check" ''
-          ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
-        '')];
+        services.openldap = {
+          enable = true;
+          settings = {
+            children = {
+              "cn=schema".includes = [
+                "${pkgs.openldap}/etc/schema/core.ldif"
+                "${pkgs.openldap}/etc/schema/cosine.ldif"
+                "${pkgs.openldap}/etc/schema/inetorgperson.ldif"
+                "${pkgs.openldap}/etc/schema/nis.ldif"
+              ];
+              "olcDatabase={1}mdb" = {
+                attrs = {
+                  objectClass = [
+                    "olcDatabaseConfig"
+                    "olcMdbConfig"
+                  ];
+                  olcDatabase = "{1}mdb";
+                  olcDbDirectory = "/var/lib/openldap/example";
+                  olcSuffix = "dc=example";
+                };
+              };
+            };
+          };
+          declarativeContents."dc=example" =
+            #ldif
+            ''
+              dn: dc=example
+              objectClass: domain
+              dc: example
 
-      environment.etc.bind-password.text = bindPassword;
+              dn: cn=mail,dc=example
+              objectClass: organizationalRole
+              objectClass: simpleSecurityObject
+              objectClass: top
+              cn: mail
+              # unsafegibberish
+              userPassword: {SSHA}JNr6l3s/RHo1LKRXqFsJg8sXznyRid8L
 
-      services.openldap = {
-        enable = true;
-        settings = {
-          children = {
-            "cn=schema".includes = [
-              "${pkgs.openldap}/etc/schema/core.ldif"
-              "${pkgs.openldap}/etc/schema/cosine.ldif"
-              "${pkgs.openldap}/etc/schema/inetorgperson.ldif"
-              "${pkgs.openldap}/etc/schema/nis.ldif"
+              dn: ou=users,dc=example
+              objectClass: organizationalUnit
+              ou: users
+
+              dn: cn=alice,ou=users,dc=example
+              entryUUID: c52f777b-a6e8-4507-80f9-c4de47e8520d
+              objectClass: inetOrgPerson
+              uid: alice
+              sn: Foo
+              mail: alice@example.com
+              # testalice
+              userPassword: {SSHA}gkJq4Dm4jfIKjxviR0WD63wMt0Ti6zMB
+
+              dn: cn=bob,ou=users,dc=example
+              entryUUID: f3b4e8ea-087f-42cc-95f0-cbfd99386092
+              objectClass: inetOrgPerson
+              objectClass: posixAccount
+              uid: bob
+              uidNumber: 9999
+              gidNumber: 9999
+              sn: Bar
+              mail: bob@example.com
+              homeDirectory: /home/bob
+              # testbob
+              userPassword: {SSHA}qqUveZGZrDrjYFnREXLDZc//y89RppVN
+
+              dn: cn=carol,ou=users,dc=example
+              entryUUID: 41240499-27e2-4fa2-be4f-4113a77661b1
+              objectClass: inetOrgPerson
+              uid: carol
+              sn: Baz
+              mail: carol@example.com
+              # testcarol
+              userPassword: {SSHA}69HOuP+OPWE+3+tDucFZxzXDC7p4e3ML
+
+              dn: cn=frank,ou=users,dc=example
+              entryUUID: ca16f594-f6b2-418f-87d3-0d02d746461f
+              objectClass: inetOrgPerson
+              uid: frank
+              sn: Moo
+              mail: frank@example.com
+              # testfrank
+              userPassword: {SSHA}xqtMl8/uJ6HEFWDzLYpAE+Wq7FvKrtkm
+            '';
+        };
+
+        systemd.services.dovecot.serviceConfig = {
+          CacheDirectory = "dovecot";
+          StateDirectory = "dovecot";
+        };
+
+        mailserver = {
+          enable = true;
+          fqdn = "mail.example.com";
+          domains = [ "example.com" ];
+          localDnsResolver = false;
+          storage.path = "/var/lib/dovecot/vmail";
+          indexDir = "/var/cache/dovecot/indices";
+
+          aliases = {
+            # Steal frank@example.com from LDAP user frank
+            "frank@example.com" = "mallory@example.com";
+          };
+
+          accounts = {
+            # Colliding local account takes precedence over LDAP account with
+            # same address.
+            "carol@example.com" = {
+              hashedPasswordFile = hashPassword carolPassword;
+            };
+            # Another account used as a virtual alias target to steal
+            # frank@example.com from the LDAP user frank
+            "mallory@example.com" = {
+              hashedPasswordFile = hashPassword malloryPassword;
+            };
+          };
+
+          ldap = {
+            enable = true;
+            uris = [
+              "ldap://"
             ];
-            "olcDatabase={1}mdb" = {
-              attrs = {
-                objectClass = [
-                  "olcDatabaseConfig"
-                  "olcMdbConfig"
-                ];
-                olcDatabase = "{1}mdb";
-                olcDbDirectory = "/var/lib/openldap/example";
-                olcSuffix = "dc=example";
+            bind = {
+              dn = "cn=mail,dc=example";
+              passwordFile = "/etc/bind-password";
+            };
+            base = "ou=users,dc=example";
+            scope = "sub";
+            attributes = {
+              # disable auth bind
+              password = "userPassword";
+            };
+          };
+
+          forwards = {
+            "bob_fw@example.com" = "bob@example.com";
+          };
+        };
+
+        specialisation.auth_bind = {
+          inheritParentConfig = true;
+          configuration = {
+            mailserver = {
+              ldap = {
+                attributes = {
+                  # enable auth bind
+                  password = lib.mkForce null;
+                };
+              };
+            };
+
+            services.openldap.settings.children = {
+              "olcDatabase={1}mdb" = {
+                attrs = {
+                  olcAccess = [
+                    # disallow access to userPassword
+                    ''
+                      to * attrs=userPassword
+                        by anonymous auth
+                        by * none
+                    ''
+
+                    # default policy (same as if we would specify none as all)
+                    ''
+                      to *
+                        by * read
+                    ''
+                  ];
+                };
               };
             };
           };
         };
-        declarativeContents."dc=example" = ''
-          dn: dc=example
-          objectClass: domain
-          dc: example
-
-          dn: cn=mail,dc=example
-          objectClass: organizationalRole
-          objectClass: simpleSecurityObject
-          objectClass: top
-          cn: mail
-          userPassword: ${bindPassword}
-
-          dn: ou=users,dc=example
-          objectClass: organizationalUnit
-          ou: users
-
-          dn: cn=alice,ou=users,dc=example
-          objectClass: inetOrgPerson
-          cn: alice
-          sn: Foo
-          mail: alice@example.com
-          userPassword: ${alicePassword}
-
-          dn: cn=bob,ou=users,dc=example
-          objectClass: inetOrgPerson
-          cn: bob
-          sn: Bar
-          mail: bob@example.com
-          userPassword: ${bobPassword}
-        '';
       };
-
-      mailserver = {
-        enable = true;
-        fqdn = "mail.example.com";
-        domains = [ "example.com" ];
-        localDnsResolver = false;
-
-        ldap = {
-          enable = true;
-          uris = [
-            "ldap://"
-          ];
-          bind = {
-            dn = "cn=mail,dc=example";
-            passwordFile = "/etc/bind-password";
-          };
-          searchBase = "ou=users,dc=example";
-          searchScope = "sub";
-        };
-
-        forwards = {
-          "bob_fw@example.com" = "bob@example.com";
-        };
-
-        vmailGroupName = "vmail";
-        vmailUID = 5000;
-
-        enableImap = false;
-      };
-    };
   };
-  testScript = ''
-    import sys
-    import re
+  testScript =
+    {
+      nodes,
+      ...
+    }:
+    # python
+    ''
+      import sys
+      import re
 
-    machine.start()
-    machine.wait_for_unit("multi-user.target")
+      machine.start()
+      machine.wait_for_unit("multi-user.target")
 
-    # This function retrieves the ldap table file from a postconf
-    # command.
-    # A key lookup is achived and the returned value is compared
-    # to the expected value.
-    def test_lookup(postconf_cmdline, key, expected):
-      conf = machine.succeed(postconf_cmdline).rstrip()
-      ldap_table_path = re.match('.* =.*ldap:(.*)', conf).group(1)
-      value = machine.succeed(f"postmap -q {key} ldap:{ldap_table_path}").rstrip()
-      try:
-        assert value == expected
-      except AssertionError:
-        print(f"Expected {conf} lookup for key '{key}' to return '{expected}, but got '{value}'", file=sys.stderr)
-        raise
+      # if the schema is broken, fail fast. helps during development.
+      machine.wait_for_unit("openldap.service")
 
-    with subtest("Test postmap lookups"):
-      test_lookup("postconf virtual_mailbox_maps", "alice@example.com", "alice@example.com")
-      test_lookup("postconf -P submission/inet/smtpd_sender_login_maps", "alice@example.com", "alice@example.com")
+      machine.wait_for_open_unix_socket("/run/rspamd/rspamd-milter.sock")
 
-      test_lookup("postconf virtual_mailbox_maps", "bob@example.com", "bob@example.com")
-      test_lookup("postconf -P submission/inet/smtpd_sender_login_maps", "bob@example.com", "bob@example.com")
+      # This function retrieves the ldap table file from a postconf
+      # command.
+      # A key lookup is achieved and the returned value is compared
+      # to the expected value.
+      def test_lookup(postconf_cmdline, key, expected):
+        conf = machine.succeed(postconf_cmdline).rstrip()
+        ldap_table_path_match = re.match('.* =.*ldap:(.*)', conf)
+        if not ldap_table_path_match:
+          raise RuntimeError(f"Failed to match LDAP table in '{postconf_cmdline}' response")
+        ldap_table_path = ldap_table_path_match.group(1)
+        value = machine.succeed(f"postmap -q {key} ldap:{ldap_table_path}").rstrip()
+        try:
+          assert value == expected
+        except AssertionError:
+          print(f"Expected {conf} lookup for key '{key}' to return '{expected}, but got '{value}'", file=sys.stderr)
+          raise
 
-    with subtest("Test doveadm lookups"):
-      machine.succeed("doveadm user -u alice@example.com")
-      machine.succeed("doveadm user -u bob@example.com")
+      with subtest("Test postmap lookups"):
+        test_lookup("postconf virtual_mailbox_maps", "alice@example.com", "alice")
+        test_lookup("postconf -P submission/inet/smtpd_sender_login_maps", "alice@example.com", "alice")
 
-    with subtest("Files containing secrets are only readable by root"):
-      machine.succeed("ls -l /run/postfix/*.cf | grep -e '-rw------- 1 root root'")
-      machine.succeed("ls -l /run/dovecot2/dovecot-ldap.conf.ext | grep -e '-rw------- 1 root root'")
+        test_lookup("postconf virtual_mailbox_maps", "bob@example.com", "bob")
+        test_lookup("postconf -P submission/inet/smtpd_sender_login_maps", "bob@example.com", "bob")
 
-    with subtest("Test account/mail address binding"):
-      machine.fail(" ".join([
-        "mail-check send-and-read",
-        "--smtp-port 587",
-        "--smtp-starttls",
-        "--smtp-host localhost",
-        "--smtp-username alice@example.com",
-        "--imap-host localhost",
-        "--imap-username bob@example.com",
-        "--from-addr bob@example.com",
-        "--to-addr aliceb@example.com",
-        "--src-password-file <(echo '${alicePassword}')",
-        "--dst-password-file <(echo '${bobPassword}')",
-        "--ignore-dkim-spf"
-      ]))
-      machine.succeed("journalctl -u postfix | grep -q 'Sender address rejected: not owned by user alice@example.com'")
+      with subtest("Test doveadm lookups"):
+        machine.succeed("doveadm user -u alice@example.com")
+        machine.succeed("doveadm user -u bob@example.com")
 
-    with subtest("Test mail delivery"):
-      machine.succeed(" ".join([
-        "mail-check send-and-read",
-        "--smtp-port 587",
-        "--smtp-starttls",
-        "--smtp-host localhost",
-        "--smtp-username alice@example.com",
-        "--imap-host localhost",
-        "--imap-username bob@example.com",
-        "--from-addr alice@example.com",
-        "--to-addr bob@example.com",
-        "--src-password-file <(echo '${alicePassword}')",
-        "--dst-password-file <(echo '${bobPassword}')",
-        "--ignore-dkim-spf"
-      ]))
+        machine.succeed("doveadm user -u alice")
+        machine.log(machine.succeed("doveadm user -u bob"))
 
-    with subtest("Test mail forwarding works"):
-      machine.succeed(" ".join([
-        "mail-check send-and-read",
-        "--smtp-port 587",
-        "--smtp-starttls",
-        "--smtp-host localhost",
-        "--smtp-username alice@example.com",
-        "--imap-host localhost",
-        "--imap-username bob@example.com",
-        "--from-addr alice@example.com",
-        "--to-addr bob_fw@example.com",
-        "--src-password-file <(echo '${alicePassword}')",
-        "--dst-password-file <(echo '${bobPassword}')",
-        "--ignore-dkim-spf"
-      ]))
+        machine.succeed("doveadm user -f uid bob@example.com | grep ${toString nodes.machine.mailserver.storage.uid}")
+        machine.succeed("doveadm user -f gid bob@example.com | grep ${toString nodes.machine.mailserver.storage.uid}")
 
-    with subtest("Test cannot send mail from forwarded address"):
-      machine.fail(" ".join([
-        "mail-check send-and-read",
-        "--smtp-port 587",
-        "--smtp-starttls",
-        "--smtp-host localhost",
-        "--smtp-username bob@example.com",
-        "--imap-host localhost",
-        "--imap-username alice@example.com",
-        "--from-addr bob_fw@example.com",
-        "--to-addr alice@example.com",
-        "--src-password-file <(echo '${bobPassword}')",
-        "--dst-password-file <(echo '${alicePassword}')",
-        "--ignore-dkim-spf"
-      ]))
-      machine.succeed("journalctl -u postfix | grep -q 'Sender address rejected: not owned by user bob@example.com'")
+        machine.succeed("doveadm user -f home bob@example.com | grep ${nodes.machine.mailserver.storage.path}/ldap/f3b4e8ea-087f-42cc-95f0-cbfd99386092")
+        machine.succeed("doveadm user -f mail_path bob@example.com | grep ${nodes.machine.mailserver.storage.path}/ldap/f3b4e8ea-087f-42cc-95f0-cbfd99386092")
+        machine.succeed("doveadm user -f mail_index_path bob@example.com | grep ${nodes.machine.mailserver.indexDir}/ldap/f3b4e8ea-087f-42cc-95f0-cbfd99386092")
 
-  '';
+      with subtest("Files containing secrets are only readable by root"):
+        machine.succeed("ls -l /run/postfix/*.cf | grep -e '-rw------- 1 root root'")
+
+      with subtest("Test account/mail address binding via explicit TLS"):
+        machine.fail(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 587",
+          "--smtp-starttls",
+          "--smtp-host localhost",
+          "--smtp-username alice",
+          "--imap-host localhost",
+          "--imap-username bob",
+          "--from-addr bob@example.com",
+          "--to-addr aliceb@example.com",
+          "--src-password-file <(echo '${alicePassword}')",
+          "--dst-password-file <(echo '${bobPassword}')",
+          "--ignore-dkim-spf"
+        ]))
+        machine.succeed("journalctl -u postfix | grep -q 'Sender address rejected: not owned by user alice'")
+
+      with subtest("Test mail delivery via implicit TLS"):
+        machine.succeed(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 465",
+          "--smtp-ssl",
+          "--smtp-host localhost",
+          "--smtp-username alice",
+          "--imap-host localhost",
+          "--imap-username bob",
+          "--from-addr alice@example.com",
+          "--to-addr bob@example.com",
+          "--src-password-file <(echo '${alicePassword}')",
+          "--dst-password-file <(echo '${bobPassword}')",
+          "--ignore-dkim-spf"
+        ]))
+
+      with subtest("Test mail forwarding via explicit TLS works"):
+        machine.succeed(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 587",
+          "--smtp-starttls",
+          "--smtp-host localhost",
+          "--smtp-username alice",
+          "--imap-host localhost",
+          "--imap-username bob",
+          "--from-addr alice@example.com",
+          "--to-addr bob_fw@example.com",
+          "--src-password-file <(echo '${alicePassword}')",
+          "--dst-password-file <(echo '${bobPassword}')",
+          "--ignore-dkim-spf"
+        ]))
+
+      with subtest("Test cannot send mail via implicit TLS from forwarded address"):
+        machine.fail(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 465",
+          "--smtp-ssl",
+          "--smtp-host localhost",
+          "--smtp-username bob",
+          "--imap-host localhost",
+          "--imap-username alice@example.com",
+          "--from-addr bob_fw@example.com",
+          "--to-addr alice@example.com",
+          "--src-password-file <(echo '${bobPassword}')",
+          "--dst-password-file <(echo '${alicePassword}')",
+          "--ignore-dkim-spf"
+        ]))
+        machine.succeed("journalctl -u postfix | grep -q 'Sender address rejected: not owned by user bob'")
+
+      with subtest("Local addresses take priority over those learnt from LDAP"):
+        # carol@example.com is routed to the local user account
+        machine.succeed(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 465",
+          "--smtp-ssl",
+          "--smtp-host localhost",
+          "--smtp-username alice", # LDAP user
+          "--imap-host localhost",
+          "--imap-username carol@example.com", # Local user
+          "--from-addr alice@example.com",
+          "--to-addr carol@example.com",
+          "--src-password-file <(echo '${alicePassword}')",
+          "--dst-password-file <(echo '${carolPassword}')",
+          "--ignore-dkim-spf"
+        ]))
+
+        # frank@example.com gets routed to mallory@example.com due to a virtual alias
+        machine.succeed(" ".join([
+          "mail-check send-and-read",
+          "--smtp-port 465",
+          "--smtp-ssl",
+          "--smtp-host localhost",
+          "--smtp-username alice", # LDAP user
+          "--imap-host localhost",
+          "--imap-username mallory@example.com", # Local user
+          "--from-addr alice@example.com",
+          "--to-addr frank@example.com",
+          "--src-password-file <(echo '${alicePassword}')",
+          "--dst-password-file <(echo '${malloryPassword}')",
+          "--ignore-dkim-spf"
+        ]))
+
+      with subtest("LDAP Authentication Binds"):
+        machine.succeed("/run/booted-system/specialisation/auth_bind/bin/switch-to-configuration test")
+        machine.wait_for_unit("openldap.service")
+        machine.succeed("doveadm auth test alice '${alicePassword}'")
+    '';
 }

tests/lib/cert.pem

@@ -0,0 +1,11 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/lib/config.nix

@@ -1,3 +1,39 @@
 {
-    security.dhparams.defaultBitSize = 2048; # minimum size required by dovecot
+  lib,
+  ...
+}:
+
+{
+  # Testing eval failures that result from stateVersion assertion is out of scope
+  mailserver.stateVersion = 999;
+
+  # Keep testing submission with explicit TLS
+  mailserver.enableSubmission = true;
+
+  # Certificate created for testing purposes from RFC9500 private key
+  # https://datatracker.ietf.org/doc/rfc9500/
+  #   openssl req -x509 -new -key key.pem \
+  #    -subj "/CN=test.localdomain" \
+  #    -sha256 -days 3650 \
+  #    -out cert.pem
+  mailserver.x509 = {
+    certificateFile = "${./cert.pem}";
+    privateKeyFile = "${./key.pem}";
+  };
+
+  # Enable second CPU core
+  virtualisation.cores = lib.mkDefault 2;
+
+  services.rspamd = {
+    # Don't make tests block on DNS requests that will never succeed
+    locals."options.inc".text = ''
+      dns {
+        nameservers = ["127.0.0.1"];
+        timeout = 0.0s;
+        retransmits = 0;
+      }
+    '';
+    # Relax `local_addrs` definition to default for tests, so mail doesn't get flagged as spam
+    overrides."options.inc".enable = false;
+  };
 }

tests/lib/key.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIObLW92AqkWunJXowVR2Z5/+yVPBaFHnEedDk5WJxk/BoAoGCCqGSM49
+AwEHoUQDQgAEQiVI+I+3gv+17KN0RFLHKh5Vj71vc75eSOkyMsxFxbFsTNEMTLjV
+uKFxOelIgsiZJXKZNCX0FBmrfpCkKklCcg==
+-----END EC PRIVATE KEY-----

tests/lib/redirect.sieve

@@ -0,0 +1,3 @@
+if address :is "from" "user1@example.com" {
+  redirect "user1@example.com";
+}

tests/minimal.nix

@@ -1,27 +0,0 @@
-#  nixos-mailserver: a simple mail server
-#  Copyright (C) 2016-2018  Robin Raymond
-#
-#  This program is free software: you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation, either version 3 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program. If not, see <http://www.gnu.org/licenses/>
-
-{
-  name = "minimal";
-
-  nodes.machine = {
-    imports = [  ./../default.nix ];
-  };
-
-  testScript = ''
-    machine.wait_for_unit("multi-user.target");
-  '';
-}

tests/multiple.nix

@@ -1,22 +1,33 @@
 # This tests is used to test features requiring several mail domains.
 
 {
+  lib,
   pkgs,
   ...
 }:
 
 let
-    hashPassword = password: pkgs.runCommand
-      "password-${password}-hashed"
-      { buildInputs = [ pkgs.mkpasswd ]; inherit password; }
+  hashPassword =
+    password:
+    pkgs.runCommand "password-${password}-hashed"
+      {
+        buildInputs = [ pkgs.mkpasswd ];
+        inherit password;
+      }
       ''
-        mkpasswd -sm bcrypt <<<"$password" > $out
+        mkpasswd -s <<<"$password" > $out
       '';
 
-    password = pkgs.writeText "password" "password";
+  password = pkgs.writeText "password" "password";
 
-    domainGenerator = domain: { pkgs, ... }: {
-      imports = [../default.nix];
+  domainGenerator =
+    domain:
+    { pkgs, ... }:
+    {
+      imports = [
+        ../default.nix
+        ./lib/config.nix
+      ];
       environment.systemPackages = with pkgs; [ netcat ];
       virtualisation.memorySize = 1024;
       mailserver = {
@@ -24,7 +35,7 @@ let
         fqdn = "mail.${domain}";
         domains = [ domain ];
         localDnsResolver = false;
-        loginAccounts = {
+        accounts = {
           "user@${domain}" = {
             hashedPasswordFile = hashPassword "password";
           };
@@ -34,8 +45,14 @@ let
       };
       services.dnsmasq = {
         enable = true;
-        settings.mx-host = [ "domain1.com,domain1,10" "domain2.com,domain2,10" ];
+        settings.mx-host = [
+          "domain1.com,domain1,10"
+          "domain2.com,domain2,10"
+        ];
       };
+
+      # breaks the test, due to running into DNS timeouts
+      services.postfix-tlspol.configurePostfix = lib.mkForce false;
     };
 
 in
@@ -44,46 +61,55 @@ in
   name = "multiple";
 
   nodes = {
-    domain1 = {...}: {
-      imports = [
-        ../default.nix
-        (domainGenerator "domain1.com")
-      ];
-      mailserver.forwards = {
-        "non-local@domain1.com" = ["user@domain2.com" "user@domain1.com"];
-        "non@domain1.com" = ["user@domain2.com" "user@domain1.com"];
+    domain1 =
+      { ... }:
+      {
+        imports = [
+          ../default.nix
+          (domainGenerator "domain1.com")
+        ];
+        mailserver.forwards = {
+          "non-local@domain1.com" = [
+            "user@domain2.com"
+            "user@domain1.com"
+          ];
+          "non@domain1.com" = [
+            "user@domain2.com"
+            "user@domain1.com"
+          ];
+        };
       };
-    };
     domain2 = domainGenerator "domain2.com";
-    client = { pkgs, ... }: {
-      environment.systemPackages = [
-        (pkgs.writeScriptBin "mail-check" ''
-          ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
-        '')];
-    };
+    client =
+      { pkgs, ... }:
+      {
+        environment.systemPackages = [
+          (pkgs.writeScriptBin "mail-check" ''
+            ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
+          '')
+        ];
+      };
   };
-  testScript = ''
-    start_all()
+  testScript =
+    # python
+    ''
+      start_all()
 
-    domain1.wait_for_unit("multi-user.target")
-    domain2.wait_for_unit("multi-user.target")
+      for domain in [domain1, domain2]:
+        domain.wait_for_unit("multi-user.target")
+        domain.wait_for_unit("dovecot.service")
 
-    # TODO put this blocking into the systemd units?
-    domain1.wait_until_succeeds(
-        "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
-    )
-    domain2.wait_until_succeeds(
-        "set +e; timeout 1 nc -U /run/rspamd/rspamd-milter.sock < /dev/null; [ $? -eq 124 ]"
-    )
+      for host in [domain1, domain2]:
+        host.wait_for_open_unix_socket("/run/rspamd/rspamd-milter.sock")
 
-    # user@domain1.com sends a mail to user@domain2.com
-    client.succeed(
-        "mail-check send-and-read --smtp-port 587 --smtp-starttls --smtp-host domain1 --from-addr user@domain1.com --imap-host domain2 --to-addr user@domain2.com --src-password-file ${password} --dst-password-file ${password} --ignore-dkim-spf"
-    )
+      # user@domain1.com sends a mail to user@domain2.com via explicit TLS
+      client.succeed(
+          "mail-check send-and-read --smtp-port 587 --smtp-starttls --smtp-host domain1 --from-addr user@domain1.com --imap-host domain2 --to-addr user@domain2.com --src-password-file ${password} --dst-password-file ${password} --ignore-dkim-spf"
+      )
 
-    # Send a mail to the address forwarded and check it is in the recipient mailbox
-    client.succeed(
-        "mail-check send-and-read --smtp-port 587 --smtp-starttls --smtp-host domain1 --from-addr user@domain1.com --imap-host domain2 --to-addr non-local@domain1.com --imap-username user@domain2.com --src-password-file ${password} --dst-password-file ${password} --ignore-dkim-spf"
-    )
-  '';
+      # Send a mail to the address forwarded via implicit TLS and check it is in the recipient mailbox
+      client.succeed(
+          "mail-check send-and-read --smtp-port 465 --smtp-ssl --smtp-host domain1 --from-addr user@domain1.com --imap-host domain2 --to-addr non-local@domain1.com --imap-username user@domain2.com --src-password-file ${password} --dst-password-file ${password} --ignore-dkim-spf"
+      )
+    '';
 }