From 1a7f3d718c5a6406b7d5b54f10f5c9c69ed90ef9 Mon Sep 17 00:00:00 2001
From: Martin Weinelt <hexa@darmstadt.ccc.de>
Date: Sun, 15 Jun 2025 03:39:44 +0200
Subject: [PATCH] treewide: reformat with nixfmt-rfc-style

---
 .hydra/declarative-jobsets.nix |  32 +-
 default.nix                    | 432 ++++++++++++++----------
 flake.nix                      | 348 +++++++++++---------
 mail-server/borgbackup.nix     |  41 ++-
 mail-server/common.nix         |  95 +++---
 mail-server/dovecot.nix        | 580 ++++++++++++++++++---------------
 mail-server/environment.nix    |  25 +-
 mail-server/kresd.nix          |   1 -
 mail-server/networking.nix     |  27 +-
 mail-server/nginx.nix          |  40 ++-
 mail-server/postfix.nix        | 476 +++++++++++++++------------
 mail-server/rsnapshot.nix      |  10 +-
 mail-server/rspamd.nix         | 406 ++++++++++++-----------
 mail-server/systemd.nix        | 115 ++++---
 mail-server/users.nix          |  71 ++--
 shell.nix                      |  19 +-
 tests/clamav.nix               | 239 +++++++-------
 tests/external.nix             | 459 +++++++++++++-------------
 tests/internal.nix             | 104 +++---
 tests/ldap.nix                 | 183 ++++++-----
 tests/multiple.nix             |  63 ++--
 21 files changed, 2086 insertions(+), 1680 deletions(-)

diff --git a/.hydra/declarative-jobsets.nix b/.hydra/declarative-jobsets.nix
index 7b99844..6877235 100644
--- a/.hydra/declarative-jobsets.nix
+++ b/.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;
@@ -41,8 +40,9 @@ let
     jobsets = desc;
   };
 
-in {
-  jobsets = pkgs.runCommand "spec-jobsets.json" {} ''
+in
+{
+  jobsets = pkgs.runCommand "spec-jobsets.json" { } ''
     cat >$out <<EOF
     ${builtins.toJSON desc}
     EOF
diff --git a/default.nix b/default.nix
index fa471bf..94b3186 100644
--- a/default.nix
+++ b/default.nix
@@ -14,7 +14,12 @@
 #  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, lib, pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 with lib;
 
@@ -56,14 +61,17 @@ in
     domains = mkOption {
       type = types.listOf types.str;
       example = [ "example.com" ];
-      default = [];
+      default = [ ];
       description = "The domains that this mail server serves.";
     };
 
     certificateDomains = mkOption {
       type = types.listOf types.str;
-      example = [ "imap.example.com" "pop3.example.com" ];
-      default = [];
+      example = [
+        "imap.example.com"
+        "pop3.example.com"
+      ];
+      default = [ ];
       description = ''
         ({option}`mailserver.certificateScheme` == `acme-nginx`)
 
@@ -79,130 +87,141 @@ in
     };
 
     loginAccounts = mkOption {
-      type = types.attrsOf (types.submodule ({ name, ... }: {
-        options = {
-          name = mkOption {
-            type = types.str;
-            example = "user1@example.com";
-            description = "Username";
-          };
+      type = types.attrsOf (
+        types.submodule (
+          { name, ... }:
+          {
+            options = {
+              name = mkOption {
+                type = types.str;
+                example = "user1@example.com";
+                description = "Username";
+              };
 
-          hashedPassword = mkOption {
-            type = with types; nullOr str;
-            default = null;
-            example = "$6$evQJs5CFQyPAW09S$Cn99Y8.QjZ2IBnSu4qf1vBxDRWkaIZWOtmu1Ddsm3.H3CFpeVc0JU4llIq8HQXgeatvYhh5O33eWG3TSpjzu6/";
-            description = ''
-              The user's hashed password. Use `mkpasswd` as follows
+              hashedPassword = mkOption {
+                type = with types; nullOr str;
+                default = null;
+                example = "$6$evQJs5CFQyPAW09S$Cn99Y8.QjZ2IBnSu4qf1vBxDRWkaIZWOtmu1Ddsm3.H3CFpeVc0JU4llIq8HQXgeatvYhh5O33eWG3TSpjzu6/";
+                description = ''
+                  The user's hashed password. Use `mkpasswd` as follows
 
-              ```
-              nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
-              ```
+                  ```
+                  nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
+                  ```
 
-              Warning: this is stored in plaintext in the Nix store!
-              Use {option}`mailserver.loginAccounts.<name>.hashedPasswordFile` instead.
-            '';
-          };
+                  Warning: this is stored in plaintext in the Nix store!
+                  Use {option}`mailserver.loginAccounts.<name>.hashedPasswordFile` instead.
+                '';
+              };
 
-          hashedPasswordFile = mkOption {
-            type = with types; nullOr path;
-            default = null;
-            example = "/run/keys/user1-passwordhash";
-            description = ''
-              A file containing the user's hashed password. Use `mkpasswd` as follows
+              hashedPasswordFile = mkOption {
+                type = with types; nullOr path;
+                default = null;
+                example = "/run/keys/user1-passwordhash";
+                description = ''
+                  A file containing the user's hashed password. Use `mkpasswd` as follows
 
-              ```
-              nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
-              ```
-            '';
-          };
+                  ```
+                  nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
+                  ```
+                '';
+              };
 
-          aliases = mkOption {
-            type = with types; listOf types.str;
-            example = ["abuse@example.com" "postmaster@example.com"];
-            default = [];
-            description = ''
-              A list of aliases of this login account.
-              Note: Use list entries like "@example.com" to create a catchAll
-              that allows sending from all email addresses in these domain.
-            '';
-          };
+              aliases = mkOption {
+                type = with types; listOf types.str;
+                example = [
+                  "abuse@example.com"
+                  "postmaster@example.com"
+                ];
+                default = [ ];
+                description = ''
+                  A list of aliases of this login account.
+                  Note: Use list entries like "@example.com" to create a catchAll
+                  that allows sending from all email addresses in these domain.
+                '';
+              };
 
-          aliasesRegexp = mkOption {
-            type = with types; listOf types.str;
-            example = [''/^tom\..*@domain\.com$/''];
-            default = [];
-            description = ''
-              Same as {option}`mailserver.aliases` but using PCRE (Perl compatible regex).
-            '';
-          };
+              aliasesRegexp = mkOption {
+                type = with types; listOf types.str;
+                example = [ ''/^tom\..*@domain\.com$/'' ];
+                default = [ ];
+                description = ''
+                  Same as {option}`mailserver.aliases` but using PCRE (Perl compatible regex).
+                '';
+              };
 
-          catchAll = mkOption {
-            type = with types; listOf (enum cfg.domains);
-            example = ["example.com" "example2.com"];
-            default = [];
-            description = ''
-              For which domains should this account act as a catch all?
-              Note: Does not allow sending from all addresses of these domains.
-            '';
-          };
+              catchAll = mkOption {
+                type = with types; listOf (enum cfg.domains);
+                example = [
+                  "example.com"
+                  "example2.com"
+                ];
+                default = [ ];
+                description = ''
+                  For which domains should this account act as a catch all?
+                  Note: Does not allow sending from all addresses of these domains.
+                '';
+              };
 
-          quota = mkOption {
-            type = with types; nullOr types.str;
-            default = null;
-            example = "2G";
-            description = ''
-              Per user quota rules. Accepted sizes are `xx k/M/G/T` with the
-              obvious meaning. Leave blank for the standard quota `100G`.
-            '';
-          };
+              quota = mkOption {
+                type = with types; nullOr types.str;
+                default = null;
+                example = "2G";
+                description = ''
+                  Per user quota rules. Accepted sizes are `xx k/M/G/T` with the
+                  obvious meaning. Leave blank for the standard quota `100G`.
+                '';
+              };
 
-          sieveScript = mkOption {
-            type = with types; nullOr lines;
-            default = null;
-            example = ''
-              require ["fileinto", "mailbox"];
+              sieveScript = mkOption {
+                type = with types; nullOr lines;
+                default = null;
+                example = ''
+                  require ["fileinto", "mailbox"];
 
-              if address :is "from" "gitlab@mg.gitlab.com" {
-                fileinto :create "GitLab";
-                stop;
-              }
+                  if address :is "from" "gitlab@mg.gitlab.com" {
+                    fileinto :create "GitLab";
+                    stop;
+                  }
 
-              # This must be the last rule, it will check if list-id is set, and
-              # file the message into the Lists folder for further investigation
-              elsif header :matches "list-id" "<?*>" {
-                fileinto :create "Lists";
-                stop;
-              }
-            '';
-            description = ''
-              Per-user sieve script.
-            '';
-          };
+                  # This must be the last rule, it will check if list-id is set, and
+                  # file the message into the Lists folder for further investigation
+                  elsif header :matches "list-id" "<?*>" {
+                    fileinto :create "Lists";
+                    stop;
+                  }
+                '';
+                description = ''
+                  Per-user sieve script.
+                '';
+              };
 
-          sendOnly = mkOption {
-            type = types.bool;
-            default = false;
-            description = ''
-              Specifies if the account should be a send-only account.
-              Emails sent to send-only accounts will be rejected from
-              unauthorized senders with the `sendOnlyRejectMessage`
-              stating the reason.
-            '';
-          };
+              sendOnly = mkOption {
+                type = types.bool;
+                default = false;
+                description = ''
+                  Specifies if the account should be a send-only account.
+                  Emails sent to send-only accounts will be rejected from
+                  unauthorized senders with the `sendOnlyRejectMessage`
+                  stating the reason.
+                '';
+              };
 
-          sendOnlyRejectMessage = mkOption {
-            type = types.str;
-            default = "This account cannot receive emails.";
-            description = ''
-              The message that will be returned to the sender when an email is
-              sent to a send-only account. Only used if the account is marked
-              as send-only.
-            '';
-          };
-        };
+              sendOnlyRejectMessage = mkOption {
+                type = types.str;
+                default = "This account cannot receive emails.";
+                description = ''
+                  The message that will be returned to the sender when an email is
+                  sent to a send-only account. Only used if the account is marked
+                  as send-only.
+                '';
+              };
+            };
 
-        config.name = mkDefault name;
-      }));
+            config.name = mkDefault name;
+          }
+        )
+      );
       example = {
         user1 = {
           hashedPassword = "$6$evQJs5CFQyPAW09S$Cn99Y8.QjZ2IBnSu4qf1vBxDRWkaIZWOtmu1Ddsm3.H3CFpeVc0JU4llIq8HQXgeatvYhh5O33eWG3TSpjzu6/";
@@ -220,13 +239,13 @@ in
         nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
         ```
       '';
-      default = {};
+      default = { };
     };
 
     ldap = {
       enable = mkEnableOption "LDAP support";
 
-      uris  = mkOption {
+      uris = mkOption {
         type = types.listOf types.str;
         example = literalExpression ''
           [
@@ -284,7 +303,11 @@ in
       };
 
       searchScope = mkOption {
-        type = types.enum [ "sub" "base" "one" ];
+        type = types.enum [
+          "sub"
+          "base"
+          "one"
+        ];
         default = "sub";
         description = ''
           Search scope below which users accounts are looked for.
@@ -419,14 +442,22 @@ in
       autoIndexExclude = mkOption {
         type = types.listOf types.str;
         default = [ ];
-        example = [ "\\Trash" "SomeFolder" "Other/*" ];
+        example = [
+          "\\Trash"
+          "SomeFolder"
+          "Other/*"
+        ];
         description = ''
           Mailboxes to exclude from automatic indexing.
         '';
       };
 
       enforced = mkOption {
-        type = types.enum [ "yes" "no" "body" ];
+        type = types.enum [
+          "yes"
+          "no"
+          "body"
+        ];
         default = "no";
         description = ''
           Fail searches when no index is available. If set to
@@ -439,7 +470,10 @@ in
       languages = mkOption {
         type = types.nonEmptyListOf types.str;
         default = [ "en" ];
-        example = [ "en" "de" ];
+        example = [
+          "en"
+          "de"
+        ];
         description = ''
           A list of languages that the full text search should detect.
           At least one language must be specified.
@@ -488,7 +522,10 @@ in
     };
 
     lmtpSaveToDetailMailbox = mkOption {
-      type = types.enum ["yes" "no"];
+      type = types.enum [
+        "yes"
+        "no"
+      ];
       default = "yes";
       description = ''
         If an email address is delimited by a "+", should it be filed into a
@@ -514,17 +551,23 @@ in
     };
 
     extraVirtualAliases = mkOption {
-      type = let
-        loginAccount = mkOptionType {
-          name = "Login Account";
-          check = account: builtins.elem account (builtins.attrNames cfg.loginAccounts);
-        };
-      in with types; attrsOf (either loginAccount (nonEmptyListOf loginAccount));
+      type =
+        let
+          loginAccount = mkOptionType {
+            name = "Login Account";
+            check = account: builtins.elem account (builtins.attrNames cfg.loginAccounts);
+          };
+        in
+        with types;
+        attrsOf (either loginAccount (nonEmptyListOf loginAccount));
       example = {
         "info@example.com" = "user1@example.com";
         "postmaster@example.com" = "user1@example.com";
         "abuse@example.com" = "user1@example.com";
-        "multi@example.com" = [ "user1@example.com" "user2@example.com" ];
+        "multi@example.com" = [
+          "user1@example.com"
+          "user2@example.com"
+        ];
       };
       description = ''
         Virtual Aliases. A virtual alias `"info@example.com" = "user1@example.com"` means that
@@ -537,7 +580,7 @@ in
         example all mails for `multi@example.com` will be forwarded to both
         `user1@example.com` and `user2@example.com`.
       '';
-      default = {};
+      default = { };
     };
 
     forwards = mkOption {
@@ -554,28 +597,34 @@ in
         can't send mail as `user@example.com`. Also, this option
         allows to forward mails to external addresses.
       '';
-      default = {};
+      default = { };
     };
 
     rejectSender = mkOption {
       type = types.listOf types.str;
-      example = [ "example.com" "spammer@example.net" ];
+      example = [
+        "example.com"
+        "spammer@example.net"
+      ];
       description = ''
         Reject emails from these addresses from unauthorized senders.
         Use if a spammer is using the same domain or the same sender over and over.
       '';
-      default = [];
+      default = [ ];
     };
 
     rejectRecipients = mkOption {
       type = types.listOf types.str;
-      example = [ "sales@example.com" "info@example.com" ];
+      example = [
+        "sales@example.com"
+        "info@example.com"
+      ];
       description = ''
         Reject emails addressed to these local addresses from unauthorized senders.
         Use if a spammer has found email addresses in a catchall domain but you do
         not want to disable the catchall.
       '';
-      default = [];
+      default = [ ];
     };
 
     vmailUID = mkOption {
@@ -673,28 +722,46 @@ in
       };
     };
 
-    certificateScheme = let
-      schemes = [ "manual" "selfsigned" "acme-nginx" "acme" ];
-      translate = i: warn "Setting mailserver.certificateScheme by number is deprecated, please use names instead: 'mailserver.certificateScheme = ${builtins.toString i}' can be replaced by 'mailserver.certificateScheme = \"${(builtins.elemAt schemes (i - 1))}\"'."
-        (builtins.elemAt schemes (i - 1));
-    in mkOption {
-      type = with types; coercedTo (enum [ 1 2 3 ]) translate (enum schemes);
-      default = "selfsigned";
-      description = ''
-        The scheme to use for managing TLS certificates:
+    certificateScheme =
+      let
+        schemes = [
+          "manual"
+          "selfsigned"
+          "acme-nginx"
+          "acme"
+        ];
+        translate =
+          i:
+          warn
+            "Setting mailserver.certificateScheme by number is deprecated, please use names instead: 'mailserver.certificateScheme = ${builtins.toString i}' can be replaced by 'mailserver.certificateScheme = \"${
+              (builtins.elemAt schemes (i - 1))
+            }\"'."
+            (builtins.elemAt schemes (i - 1));
+      in
+      mkOption {
+        type =
+          with types;
+          coercedTo (enum [
+            1
+            2
+            3
+          ]) translate (enum schemes);
+        default = "selfsigned";
+        description = ''
+          The scheme to use for managing TLS certificates:
 
-        1. `manual`: you specify locations via {option}`mailserver.certificateFile` and
-           {option}`mailserver.keyFile` and manually copy certificates there.
-        2. `selfsigned`: you let the server create new (self-signed) certificates on the fly.
-        3. `acme-nginx`: you let the server request certificates from [Let's Encrypt](https://letsencrypt.org)
-           via NixOS' ACME module. By default, this will set up a stripped-down Nginx server for
-           {option}`mailserver.fqdn` and open port 80. For this to work, the FQDN must be properly
-           configured to point to your server (see the [setup guide](setup-guide.rst) for more information).
-        4. `acme`: you already have an ACME certificate set up (for example, you're already running a TLS-enabled
-           Nginx server on the FQDN). This is better than `manual` because the appropriate services will be reloaded
-           when the certificate is renewed.
-      '';
-    };
+          1. `manual`: you specify locations via {option}`mailserver.certificateFile` and
+             {option}`mailserver.keyFile` and manually copy certificates there.
+          2. `selfsigned`: you let the server create new (self-signed) certificates on the fly.
+          3. `acme-nginx`: you let the server request certificates from [Let's Encrypt](https://letsencrypt.org)
+             via NixOS' ACME module. By default, this will set up a stripped-down Nginx server for
+             {option}`mailserver.fqdn` and open port 80. For this to work, the FQDN must be properly
+             configured to point to your server (see the [setup guide](setup-guide.rst) for more information).
+          4. `acme`: you already have an ACME certificate set up (for example, you're already running a TLS-enabled
+             Nginx server on the FQDN). This is better than `manual` because the appropriate services will be reloaded
+             when the certificate is renewed.
+        '';
+      };
 
     certificateFile = mkOption {
       type = types.path;
@@ -851,7 +918,10 @@ in
     };
 
     dkimKeyType = mkOption {
-      type = types.enum [ "rsa" "ed25519" ];
+      type = types.enum [
+        "rsa"
+        "ed25519"
+      ];
       default = "rsa";
       description = ''
         The key type used for generating DKIM keys. ED25519 was introduced in RFC6376 (2018).
@@ -864,16 +934,16 @@ in
     };
 
     dkimKeyBits = mkOption {
-        type = types.int;
-        default = 1024;
-        description = ''
-            How many bits in generated DKIM keys. RFC6376 advises minimum 1024-bit keys.
+      type = types.int;
+      default = 1024;
+      description = ''
+        How many bits in generated DKIM keys. RFC6376 advises minimum 1024-bit keys.
 
-            If you have already deployed a key with a different number of bits than specified
-            here, then you should use a different selector ({option}`mailserver.dkimSelector`). In order to get
-            this package to generate a key with the new number of bits, you will either have to
-            change the selector or delete the old key file.
-        '';
+        If you have already deployed a key with a different number of bits than specified
+        here, then you should use a different selector ({option}`mailserver.dkimSelector`). In order to get
+        this package to generate a key with the new number of bits, you will either have to
+        change the selector or delete the old key file.
+      '';
     };
 
     dmarcReporting = {
@@ -938,7 +1008,7 @@ in
 
       excludeDomains = mkOption {
         type = types.listOf types.str;
-        default = [];
+        default = [ ];
         description = ''
           List of domains or eSLDs to be excluded from DMARC reports.
         '';
@@ -1150,7 +1220,15 @@ in
 
       compression = {
         method = mkOption {
-          type = types.nullOr (types.enum ["none" "lz4" "zstd" "zlib" "lzma"]);
+          type = types.nullOr (
+            types.enum [
+              "none"
+              "lz4"
+              "zstd"
+              "zlib"
+              "lzma"
+            ]
+          );
           default = null;
           description = "Leaving this unset allows borg to choose. The default for borg 1.1.4 is lz4.";
         };
@@ -1208,14 +1286,14 @@ in
 
       locations = mkOption {
         type = types.listOf types.path;
-        default = [cfg.mailDirectory];
+        default = [ cfg.mailDirectory ];
         defaultText = lib.literalExpression "[ config.mailserver.mailDirectory ]";
         description = "The locations that are to be backed up by borg.";
       };
 
       extraArgumentsForInit = mkOption {
         type = types.listOf types.str;
-        default = ["--critical"];
+        default = [ "--critical" ];
         description = "Additional arguments to add to the borg init command line.";
       };
 
@@ -1295,9 +1373,9 @@ in
       cronIntervals = mkOption {
         type = types.attrsOf types.str;
         default = {
-                   # minute, hour, day-in-month, month, weekday (0 = sunday)
+          # minute, hour, day-in-month, month, weekday (0 = sunday)
           hourly = " 0  *  *  *  *"; # Every full hour
-          daily  = "30  3  *  *  *"; # Every day at 3:30
+          daily = "30  3  *  *  *"; # Every day at 3:30
           weekly = " 0  5  *  *  0"; # Every sunday at 5:00 AM
         };
         description = ''
@@ -1311,29 +1389,29 @@ in
 
   imports = [
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "maintenance" "enable" ] ''
-    This option is not needed for fts-flatcurve
+      This option is not needed for fts-flatcurve
     '')
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "maintenance" "onCalendar" ] ''
-    This option is not needed for fts-flatcurve
+      This option is not needed for fts-flatcurve
     '')
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "maintenance" "randomizedDelaySec" ] ''
-    This option is not needed for fts-flatcurve
+      This option is not needed for fts-flatcurve
     '')
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "minSize" ] ''
-    This option is not supported by fts-flatcurve
+      This option is not supported by fts-flatcurve
     '')
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "maxSize" ] ''
-    This option is not needed since fts-xapian 1.8.3
+      This option is not needed since fts-xapian 1.8.3
     '')
     (lib.mkRemovedOptionModule [ "mailserver" "fullTextSearch" "indexAttachments" ] ''
-    Text attachments are always indexed since fts-xapian 1.4.8
+      Text attachments are always indexed since fts-xapian 1.4.8
     '')
     (lib.mkRenamedOptionModule
       [ "mailserver" "rebootAfterKernelUpgrade" "enable" ]
       [ "system" "autoUpgrade" "allowReboot" ]
     )
     (lib.mkRemovedOptionModule [ "mailserver" "rebootAfterKernelUpgrade" "method" ] ''
-    Use `system.autoUpgrade` instead.
+      Use `system.autoUpgrade` instead.
     '')
     ./mail-server/assertions.nix
     ./mail-server/borgbackup.nix
diff --git a/flake.nix b/flake.nix
index 641a858..18757c5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,177 +20,205 @@
     };
   };
 
-  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.${system};
-      }
-    ];
-    testNames = [
-      "clamav"
-      "external"
-      "internal"
-      "ldap"
-      "multiple"
-    ];
+  outputs =
+    {
+      self,
+      blobs,
+      git-hooks,
+      nixpkgs,
+      nixpkgs-25_05,
+      ...
+    }:
+    let
+      lib = nixpkgs.lib;
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${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"
+      ];
 
-    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;
-          nixfmt-rfc-style.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";
+                  domains = [
+                    "example.com"
+                  ];
+                  dmarcReporting = {
+                    organizationName = "Example Corp";
+                    domain = "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"
+          ".*\\.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.${system}.run {
+          src = ./.;
+          hooks = {
+            # docs
+            markdownlint = {
+              enable = true;
+              settings.configuration = {
+                # Max line length, doesn't seem to correclty account for lines containing links
+                # https://github.com/DavidAnson/markdownlint/blob/main/doc/md013.md
+                MD013 = false;
+              };
+            };
+            rstcheck = {
+              enable = true;
+              package = pkgs.rstcheckWithSphinx;
+              entry = lib.getExe pkgs.rstcheckWithSphinx;
+              files = "\\.rst$";
+            };
+
+            # nix
+            deadnix.enable = true;
+            nixfmt-rfc-style.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.${system}.default; # compatibility
+      packages.${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.${system} = pkgs.nixfmt-tree;
-  };
+      formatter.${system} = pkgs.nixfmt-tree;
+    };
 }
diff --git a/mail-server/borgbackup.nix b/mail-server/borgbackup.nix
index ef83b0d..51ae986 100644
--- a/mail-server/borgbackup.nix
+++ b/mail-server/borgbackup.nix
@@ -14,28 +14,44 @@
 #  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.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;
@@ -55,7 +71,8 @@ let
     ${passphraseFragment} ${pkgs.borgbackup}/bin/borg create ${extraCreateArgs} ${compression} ::${name} ${locations}
     ${cmdPostexec}
   '';
-in {
+in
+{
   config = lib.mkIf (config.mailserver.enable && cfg.enable) {
     environment.systemPackages = with pkgs; [
       borgbackup
diff --git a/mail-server/common.nix b/mail-server/common.nix
index 813a5f4..cb044b6 100644
--- a/mail-server/common.nix
+++ b/mail-server/common.nix
@@ -14,57 +14,76 @@
 #  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";
+  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";
 
   # 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";
+  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";
 
-  passwordFiles = let
-    mkHashFile = name: hash: pkgs.writeText "${builtins.hashString "sha256" name}-password-hash" hash;
-  in
-    lib.mapAttrs (name: value:
-    if value.hashedPasswordFile == null then
-      builtins.toString (mkHashFile name value.hashedPassword)
-    else value.hashedPasswordFile) cfg.loginAccounts;
+  passwordFiles =
+    let
+      mkHashFile = name: hash: pkgs.writeText "${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;
 
   # 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-${name}" ''
+      #!${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}
+    '';
 
 }
diff --git a/mail-server/dovecot.nix b/mail-server/dovecot.nix
index c6e5587..148befc 100644
--- a/mail-server/dovecot.nix
+++ b/mail-server/dovecot.nix
@@ -14,7 +14,12 @@
 #  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,
+  ...
+}:
 
 with (import ./common.nix { inherit config pkgs lib; });
 
@@ -28,10 +33,14 @@ let
   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}${if n==1 then "" else toString n}";
-    value = x;
-  }) attrs);
+  listToMultiAttrs =
+    keyPrefix: attrs:
+    lib.listToAttrs (
+      lib.imap1 (n: x: {
+        name = "${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";
@@ -39,9 +48,7 @@ let
   # maildir in format "/${domain}/${user}"
   dovecotMaildir =
     "maildir:${cfg.mailDirectory}/%{domain}/%{username}${maildirLayoutAppendix}${maildirUTF8FolderNames}"
-    + (lib.optionalString (cfg.indexDir != null)
-       ":INDEX=${cfg.indexDir}/%{domain}/%{username}"
-      );
+    + (lib.optionalString (cfg.indexDir != null) ":INDEX=${cfg.indexDir}/%{domain}/%{username}");
 
   postfixCfg = config.services.postfix;
 
@@ -51,7 +58,7 @@ let
       ldap_version = 3
       uris = ${lib.concatStringsSep " " cfg.ldap.uris}
       ${lib.optionalString cfg.ldap.startTls ''
-      tls = yes
+        tls = yes
       ''}
       tls_require_cert = hard
       tls_ca_cert_file = ${cfg.ldap.tlsCAFile}
@@ -61,11 +68,11 @@ let
       base = ${cfg.ldap.searchBase}
       scope = ${mkLdapSearchScope cfg.ldap.searchScope}
       ${lib.optionalString (cfg.ldap.dovecot.userAttrs != null) ''
-      user_attrs = ${cfg.ldap.dovecot.userAttrs}
+        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_attrs = ${cfg.ldap.dovecot.passAttrs}
       ''}
       pass_filter = ${cfg.ldap.dovecot.passFilter}
     '';
@@ -93,7 +100,9 @@ let
     # Prevent world-readable password files, even temporarily.
     umask 077
 
-    for f in ${builtins.toString (lib.mapAttrsToList (name: _: passwordFiles."${name}") cfg.loginAccounts)}; do
+    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
@@ -101,34 +110,49 @@ let
     done
 
     cat <<EOF > ${passwdFile}
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: _:
-      "${name}:${"$(head -n 1 ${passwordFiles."${name}"})"}::::::"
-    ) cfg.loginAccounts)}
+    ${lib.concatStringsSep "\n" (
+      lib.mapAttrsToList (
+        name: _: "${name}:${"$(head -n 1 ${passwordFiles."${name}"})"}::::::"
+      ) cfg.loginAccounts
+    )}
     EOF
 
     cat <<EOF > ${userdbFile}
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value:
-      "${name}:::::::"
+    ${lib.concatStringsSep "\n" (
+      lib.mapAttrsToList (
+        name: value:
+        "${name}:::::::"
         + lib.optionalString (value.quota != null) "userdb_quota_rule=*:storage=${value.quota}"
-    ) cfg.loginAccounts)}
+      ) cfg.loginAccounts
+    )}
     EOF
   '';
 
-  junkMailboxes = builtins.attrNames (lib.filterAttrs (_: v: v ? "specialUse" && v.specialUse == "Junk") cfg.mailboxes);
+  junkMailboxes = builtins.attrNames (
+    lib.filterAttrs (_: v: v ? "specialUse" && v.specialUse == "Junk") cfg.mailboxes
+  );
   junkMailboxNumber = builtins.length junkMailboxes;
   # The assertion garantees 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
-  );
+  mkLdapSearchScope =
+    scope:
+    (
+      if scope == "sub" then
+        "subtree"
+      else if scope == "one" then
+        "onelevel"
+      else
+        scope
+    );
 
   ftsPluginSettings = {
     fts = "flatcurve";
     fts_languages = listToLine cfg.fullTextSearch.languages;
-    fts_tokenizers = listToLine [ "generic" "email-address" ];
+    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;
@@ -139,255 +163,283 @@ let
 
 in
 {
-  config = with cfg; lib.mkIf enable {
-    assertions = [
-      {
-        assertion = junkMailboxNumber == 1;
-        message = "nixos-mailserver requires exactly one dovecot mailbox with the 'special use' flag set to 'Junk' (${builtins.toString junkMailboxNumber} have been found)";
-      }
-    ];
-
-    warnings =
-      lib.optional (
-        (builtins.length cfg.fullTextSearch.languages > 1) &&
-        (builtins.elem "stopwords" cfg.fullTextSearch.filters)
-      ) ''
-        Using stopwords in `mailserver.fullTextSearch.filters` with multiple
-        languages in `mailserver.fullTextSearch.languages` configured WILL
-        cause some searches to fail.
-
-        The recommended solution is to NOT use the stopword filter when
-        multiple languages are present in the configuration.
-      ''
-    ;
-
-    # for sieve-test. Shelling it in on demand usually doesnt' work, as it reads
-    # the global config and tries to open shared libraries configured in there,
-    # which are usually not compatible.
-    environment.systemPackages = [
-      pkgs.dovecot_pigeonhole
-    ] ++ lib.optional cfg.fullTextSearch.enable pkgs.dovecot-fts-flatcurve;
-
-    # For compatibility with python imaplib
-    environment.etc."dovecot/modules".source = "/run/current-system/sw/lib/dovecot/modules";
-
-    services.dovecot2 = {
-      enable = true;
-      enableImap = enableImap || enableImapSsl;
-      enablePop3 = enablePop3 || enablePop3Ssl;
-      enablePAM = false;
-      enableQuota = true;
-      mailGroup = vmailGroupName;
-      mailUser = vmailUserName;
-      mailLocation = dovecotMaildir;
-      sslServerCert = certificatePath;
-      sslServerKey = keyPath;
-      enableDHE = lib.mkDefault false;
-      enableLmtp = true;
-      mailPlugins.globally.enable = lib.optionals cfg.fullTextSearch.enable [
-        "fts"
-        "fts_flatcurve"
+  config =
+    with cfg;
+    lib.mkIf enable {
+      assertions = [
+        {
+          assertion = junkMailboxNumber == 1;
+          message = "nixos-mailserver requires exactly one dovecot mailbox with the 'special use' flag set to 'Junk' (${builtins.toString junkMailboxNumber} have been found)";
+        }
       ];
-      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);
+      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.
 
-      sieve = {
-        extensions = [
-          "fileinto"
+            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.optional cfg.fullTextSearch.enable pkgs.dovecot-fts-flatcurve;
+
+      # For compatibility with python imaplib
+      environment.etc."dovecot/modules".source = "/run/current-system/sw/lib/dovecot/modules";
+
+      services.dovecot2 = {
+        enable = true;
+        enableImap = enableImap || enableImapSsl;
+        enablePop3 = enablePop3 || enablePop3Ssl;
+        enablePAM = false;
+        enableQuota = true;
+        mailGroup = vmailGroupName;
+        mailUser = vmailUserName;
+        mailLocation = dovecotMaildir;
+        sslServerCert = certificatePath;
+        sslServerKey = keyPath;
+        enableDHE = lib.mkDefault false;
+        enableLmtp = true;
+        mailPlugins.globally.enable = lib.optionals cfg.fullTextSearch.enable [
+          "fts"
+          "fts_flatcurve"
         ];
+        protocols = lib.optional cfg.enableManageSieve "sieve";
 
-        scripts.after = builtins.toFile "spam.sieve" ''
-          require "fileinto";
+        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);
 
-          if header :is "X-Spam" "Yes" {
-              fileinto "${junkMailboxName}";
-              stop;
+        sieve = {
+          extensions = [
+            "fileinto"
+          ];
+
+          scripts.after = builtins.toFile "spam.sieve" ''
+            require "fileinto";
+
+            if header :is "X-Spam" "Yes" {
+                fileinto "${junkMailboxName}";
+                stop;
+            }
+          '';
+
+          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")
+          ];
+        };
+
+        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;
           }
-        '';
-
-        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")
         ];
+
+        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}
+
+          # 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 = TLSv1.2
+          ssl_prefer_server_ciphers = no
+          ssl_curve_list = X25519:prime256v1:secp384r1
+
+          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 = ${ldapConfFile}
+              default_fields = home=${cfg.mailDirectory}/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
+        '';
       };
 
-      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;
-        }
-      ];
+      systemd.services.dovecot2 = {
+        preStart =
+          ''
+            ${genPasswdScript}
+          ''
+          + (lib.optionalString cfg.ldap.enable setPwdInLdapConfFile);
+      };
 
-      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}
-
-        # 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 = TLSv1.2
-        ssl_prefer_server_ciphers = no
-        ssl_curve_list = X25519:prime256v1:secp384r1
-
-        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 = ${ldapConfFile}
-          default_fields = home=${cfg.mailDirectory}/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
-      '';
+      systemd.services.postfix.restartTriggers = [
+        genPasswdScript
+      ] ++ (lib.optional cfg.ldap.enable [ setPwdInLdapConfFile ]);
     };
-
-    systemd.services.dovecot2 = {
-      preStart = ''
-        ${genPasswdScript}
-      '' + (lib.optionalString cfg.ldap.enable setPwdInLdapConfFile);
-    };
-
-    systemd.services.postfix.restartTriggers = [ genPasswdScript ] ++ (lib.optional cfg.ldap.enable [setPwdInLdapConfFile]);
-  };
 }
diff --git a/mail-server/environment.nix b/mail-server/environment.nix
index b4326a1..b853211 100644
--- a/mail-server/environment.nix
+++ b/mail-server/environment.nix
@@ -14,15 +14,28 @@
 #  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 =
+    with cfg;
+    lib.mkIf enable {
+      environment.systemPackages =
+        with pkgs;
+        [
+          dovecot
+          openssh
+          postfix
+          rspamd
+        ]
+        ++ (if certificateScheme == "selfsigned" then [ openssl ] else [ ]);
+    };
 }
diff --git a/mail-server/kresd.nix b/mail-server/kresd.nix
index 230bdea..3920534 100644
--- a/mail-server/kresd.nix
+++ b/mail-server/kresd.nix
@@ -24,4 +24,3 @@ in
     services.kresd.enable = true;
   };
 }
-
diff --git a/mail-server/networking.nix b/mail-server/networking.nix
index 6af186a..587a8ae 100644
--- a/mail-server/networking.nix
+++ b/mail-server/networking.nix
@@ -20,18 +20,21 @@ let
   cfg = config.mailserver;
 in
 {
-  config = with cfg; lib.mkIf (enable && openFirewall) {
+  config =
+    with cfg;
+    lib.mkIf (enable && 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;
+      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;
+      };
     };
-  };
 }
diff --git a/mail-server/nginx.nix b/mail-server/nginx.nix
index a037f56..27de2fe 100644
--- a/mail-server/nginx.nix
+++ b/mail-server/nginx.nix
@@ -14,8 +14,12 @@
 #  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,
+  ...
+}:
 
 with (import ./common.nix { inherit config lib pkgs; });
 
@@ -23,20 +27,22 @@ 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."${cfg.fqdn}" = {
-        serverName = cfg.fqdn;
-        serverAliases = cfg.certificateDomains;
-        forceSSL = true;
-        enableACME = true;
-      };
-    };
+  config =
+    lib.mkIf (cfg.enable && (cfg.certificateScheme == "acme" || cfg.certificateScheme == "acme-nginx"))
+      {
+        services.nginx = lib.mkIf (cfg.certificateScheme == "acme-nginx") {
+          enable = true;
+          virtualHosts."${cfg.fqdn}" = {
+            serverName = cfg.fqdn;
+            serverAliases = cfg.certificateDomains;
+            forceSSL = true;
+            enableACME = true;
+          };
+        };
 
-    security.acme.certs."${cfg.acmeCertificateName}".reloadServices = [
-      "postfix.service"
-      "dovecot2.service"
-    ];
-  };
+        security.acme.certs."${cfg.acmeCertificateName}".reloadServices = [
+          "postfix.service"
+          "dovecot2.service"
+        ];
+      };
 }
diff --git a/mail-server/postfix.nix b/mail-server/postfix.nix
index 9fb316f..4237efc 100644
--- a/mail-server/postfix.nix
+++ b/mail-server/postfix.nix
@@ -14,7 +14,12 @@
 #  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,
+  ...
+}:
 
 with (import ./common.nix { inherit config pkgs lib; });
 
@@ -28,31 +33,55 @@ let
   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: { "${from}" = to; }) (value.aliases ++ lib.singleton name)
+      ) cfg.loginAccounts
+    )
+  );
+  regex_valiases_postfix = mergeLookupTables (
+    lib.flatten (
+      lib.mapAttrsToList (
+        name: value:
+        let
+          to = name;
+        in
+        map (from: { "${from}" = to; }) value.aliasesRegexp
+      ) cfg.loginAccounts
+    )
+  );
 
   # 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.loginAccounts
+    )
+  );
 
   # 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;
@@ -61,37 +90,49 @@ let
   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.loginAccounts)
+  );
+  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") 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);
@@ -103,45 +144,51 @@ 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}
@@ -186,164 +233,183 @@ let
   };
 in
 {
-  config = with cfg; lib.mkIf enable {
+  config =
+    with cfg;
+    lib.mkIf enable {
 
-    systemd.services.postfix-setup = lib.mkIf cfg.ldap.enable {
-      preStart = ''
-        ${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;
-      mapFiles."regex_vaccounts" = regex_vaccounts_file;
-      mapFiles."denied_recipients" = denied_recipients_file;
-      mapFiles."reject_senders" = reject_senders_file;
-      mapFiles."reject_recipients" = reject_recipients_file;
-      enableSubmission = cfg.enableSubmission;
-      enableSubmissions = cfg.enableSubmissionSsl;
-      virtual = lookupTableToString (mergeLookupTables [all_valiases_postfix catchAllPostfix forwards]);
-
-      config = {
-        smtpd_tls_chain_files = [
-          "${keyPath}"
-          "${certificatePath}"
+      systemd.services.postfix-setup = lib.mkIf cfg.ldap.enable {
+        preStart = ''
+          ${appendPwdInVirtualMailboxMap}
+          ${appendPwdInSenderLoginMap}
+        '';
+        restartTriggers = [
+          appendPwdInVirtualMailboxMap
+          appendPwdInSenderLoginMap
         ];
+      };
 
-        # Extra Config
-        mydestination = "";
-        recipient_delimiter = cfg.recipientDelimiter;
-        smtpd_banner = "${fqdn} ESMTP NO UCE";
-        disable_vrfy_command = true;
-        message_size_limit = toString cfg.messageSizeLimit;
-
-        # virtual mail system
-        virtual_uid_maps = "static:5000";
-        virtual_gid_maps = "static:5000";
-        virtual_mailbox_base = mailDirectory;
-        virtual_mailbox_domains = vhosts_file;
-        virtual_mailbox_maps = [
-          (mappedFile "valias")
-        ] ++ lib.optionals cfg.ldap.enable [
-          "ldap:${ldapVirtualMailboxMapFile}"
-        ] ++ lib.optionals (regex_valiases_postfix != {}) [
-          (mappedRegexFile "regex_valias")
-        ];
-        virtual_alias_maps = lib.mkAfter (lib.optionals (regex_valiases_postfix != {}) [
-          (mappedRegexFile "regex_valias")
+      services.postfix = {
+        enable = true;
+        hostname = "${sendingFqdn}";
+        networksStyle = "host";
+        mapFiles."valias" = valiases_file;
+        mapFiles."regex_valias" = regex_valiases_file;
+        mapFiles."vaccounts" = vaccounts_file;
+        mapFiles."regex_vaccounts" = regex_vaccounts_file;
+        mapFiles."denied_recipients" = denied_recipients_file;
+        mapFiles."reject_senders" = reject_senders_file;
+        mapFiles."reject_recipients" = reject_recipients_file;
+        enableSubmission = cfg.enableSubmission;
+        enableSubmissions = cfg.enableSubmissionSsl;
+        virtual = lookupTableToString (mergeLookupTables [
+          all_valiases_postfix
+          catchAllPostfix
+          forwards
         ]);
-        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";
 
-        # 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"
-        ];
+        config = {
+          smtpd_tls_chain_files = [
+            "${keyPath}"
+            "${certificatePath}"
+          ];
 
-        # reject selected senders
-        smtpd_sender_restrictions = [
-          "check_sender_access ${mappedFile "reject_senders"}"
-        ];
+          # Extra Config
+          mydestination = "";
+          recipient_delimiter = cfg.recipientDelimiter;
+          smtpd_banner = "${fqdn} ESMTP NO UCE";
+          disable_vrfy_command = true;
+          message_size_limit = toString cfg.messageSizeLimit;
 
-        smtpd_recipient_restrictions = [
-          # reject selected recipients
-          "check_recipient_access ${mappedFile "denied_recipients"}"
-          "check_recipient_access ${mappedFile "reject_recipients"}"
-          # quota checking
-          "check_policy_service unix:/run/dovecot2/quota-status"
-        ];
+          # virtual mail system
+          virtual_uid_maps = "static:5000";
+          virtual_gid_maps = "static:5000";
+          virtual_mailbox_base = mailDirectory;
+          virtual_mailbox_domains = vhosts_file;
+          virtual_mailbox_maps =
+            [
+              (mappedFile "valias")
+            ]
+            ++ lib.optionals cfg.ldap.enable [
+              "ldap:${ldapVirtualMailboxMapFile}"
+            ]
+            ++ 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";
 
-        # TLS for incoming mail is optional
-        smtpd_tls_security_level = "may";
+          # 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"
+          ];
 
-        # But required for authentication attempts
-        smtpd_tls_auth_only = true;
+          # reject selected senders
+          smtpd_sender_restrictions = [
+            "check_sender_access ${mappedFile "reject_senders"}"
+          ];
 
-        # TLS versions supported for the SMTP server
-        smtpd_tls_protocols = ">=TLSv1.2";
-        smtpd_tls_mandatory_protocols = ">=TLSv1.2";
+          smtpd_recipient_restrictions = [
+            # reject selected recipients
+            "check_recipient_access ${mappedFile "denied_recipients"}"
+            "check_recipient_access ${mappedFile "reject_recipients"}"
+            # quota checking
+            "check_policy_service unix:/run/dovecot2/quota-status"
+          ];
 
-        # Require ciphersuites that OpenSSL classifies as "High"
-        smtpd_tls_ciphers = "high";
-        smtpd_tls_mandatory_ciphers = "high";
+          # TLS for incoming mail is optional
+          smtpd_tls_security_level = "may";
 
-        # Exclude cipher suites with undesirable properties
-        smtpd_tls_exclude_ciphers = "eNULL, aNULL";
-        smtpd_tls_mandatory_exclude_ciphers = "eNULL, aNULL";
+          # But required for authentication attempts
+          smtpd_tls_auth_only = true;
 
-        # Opportunistic DANE support when delivering mail to other servers
-        # https://www.postfix.org/postconf.5.html#smtp_tls_security_level
-        smtp_dns_support_level = "dnssec";
-        smtp_tls_security_level = "dane";
+          # TLS versions supported for the SMTP server
+          smtpd_tls_protocols = ">=TLSv1.2";
+          smtpd_tls_mandatory_protocols = ">=TLSv1.2";
 
-        # 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"
+          smtpd_tls_ciphers = "high";
+          smtpd_tls_mandatory_ciphers = "high";
 
-        # Require ciphersuites that OpenSSL classifies as "High"
-        smtp_tls_ciphers = "high";
-        smtp_tls_mandatory_ciphers = "high";
+          # Exclude cipher suites with undesirable properties
+          smtpd_tls_exclude_ciphers = "eNULL, aNULL";
+          smtpd_tls_mandatory_exclude_ciphers = "eNULL, aNULL";
 
-        # Exclude ciphersuites with undesirable properties
-        smtp_tls_exclude_ciphers = "eNULL, aNULL";
-        smtp_tls_mandatory_exclude_ciphers = "eNULL, aNULL";
+          # Opportunistic DANE support when delivering mail to other servers
+          # https://www.postfix.org/postconf.5.html#smtp_tls_security_level
+          smtp_dns_support_level = "dnssec";
+          smtp_tls_security_level = "dane";
 
-        # 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
-        # https://ssl-config.mozilla.org/#server=postfix&version=3.10&config=intermediate&openssl=3.4.1&guideline=5.7
-        tls_eecdh_auto_curves = [
-          "X25519"
-          "prime256v1"
-          "secp384r1"
-        ];
+          # TLS versions supported for the SMTP client
+          smtp_tls_protocols = ">=TLSv1.2";
+          smtp_tls_mandatory_protocols = ">=TLSv1.2";
 
-        # Disable FFDHE on TLSv1.3 because it is slower than elliptic curves
-        # https://www.postfix.org/postconf.5.html#tls_ffdhe_auto_groups
-        tls_ffdhe_auto_groups = [ ];
+          # Require ciphersuites that OpenSSL classifies as "High"
+          smtp_tls_ciphers = "high";
+          smtp_tls_mandatory_ciphers = "high";
 
-        # As long as all cipher suites are considered safe, let the client use its preferred cipher
-        tls_preempt_cipherlist = false;
+          # Exclude ciphersuites with undesirable properties
+          smtp_tls_exclude_ciphers = "eNULL, aNULL";
+          smtp_tls_mandatory_exclude_ciphers = "eNULL, aNULL";
 
-        # Log only a summary message on TLS handshake completion
-        smtp_tls_loglevel = "1";
-        smtpd_tls_loglevel = "1";
+          # 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
+          # https://ssl-config.mozilla.org/#server=postfix&version=3.10&config=intermediate&openssl=3.4.1&guideline=5.7
+          tls_eecdh_auto_curves = [
+            "X25519"
+            "prime256v1"
+            "secp384r1"
+          ];
 
-        smtpd_milters = smtpdMilters;
-        non_smtpd_milters = lib.mkIf cfg.dkimSigning [ "unix:/run/rspamd/rspamd-milter.sock" ];
-        milter_protocol = "6";
-        milter_mail_macros = "i {mail_addr} {client_addr} {client_name} {auth_authen}";
-      };
+          # Disable FFDHE on TLSv1.3 because it is slower than elliptic curves
+          # https://www.postfix.org/postconf.5.html#tls_ffdhe_auto_groups
+          tls_ffdhe_auto_groups = [ ];
 
-      submissionOptions = submissionOptions;
-      submissionsOptions = submissionOptions;
+          # As long as all cipher suites are considered safe, let the client use its preferred cipher
+          tls_preempt_cipherlist = false;
 
-      masterConfig = {
-        "lmtp" = {
-          # Add headers when delivering, see http://www.postfix.org/smtp.8.html
-          # D => Delivered-To, O => X-Original-To, R => Return-Path
-          args = [ "flags=O" ];
+          # Log only a summary message on TLS handshake completion
+          smtp_tls_loglevel = "1";
+          smtpd_tls_loglevel = "1";
+
+          smtpd_milters = smtpdMilters;
+          non_smtpd_milters = lib.mkIf cfg.dkimSigning [ "unix:/run/rspamd/rspamd-milter.sock" ];
+          milter_protocol = "6";
+          milter_mail_macros = "i {mail_addr} {client_addr} {client_name} {auth_authen}";
         };
-        "submission-header-cleanup" = {
-          type = "unix";
-          private = false;
-          chroot = false;
-          maxproc = 0;
-          command = "cleanup";
-          args = ["-o" "header_checks=pcre:${submissionHeaderCleanupRules}"];
+
+        submissionOptions = submissionOptions;
+        submissionsOptions = submissionOptions;
+
+        masterConfig = {
+          "lmtp" = {
+            # Add headers when delivering, see http://www.postfix.org/smtp.8.html
+            # D => Delivered-To, O => X-Original-To, R => Return-Path
+            args = [ "flags=O" ];
+          };
+          "submission-header-cleanup" = {
+            type = "unix";
+            private = false;
+            chroot = false;
+            maxproc = 0;
+            command = "cleanup";
+            args = [
+              "-o"
+              "header_checks=pcre:${submissionHeaderCleanupRules}"
+            ];
+          };
         };
       };
     };
-  };
 }
diff --git a/mail-server/rsnapshot.nix b/mail-server/rsnapshot.nix
index a801c24..de4f13e 100644
--- a/mail-server/rsnapshot.nix
+++ b/mail-server/rsnapshot.nix
@@ -14,7 +14,12 @@
 #  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,
+  ...
+}:
 
 with lib;
 
@@ -38,7 +43,8 @@ let
     ${cfg.backup.cmdPostexec}
   '';
   postexecString = optionalString postexecDefined "cmd_postexec	${postexecWrapped}";
-in {
+in
+{
   config = mkIf (cfg.enable && cfg.backup.enable) {
     services.rsnapshot = {
       enable = true;
diff --git a/mail-server/rspamd.nix b/mail-server/rspamd.nix
index ab5113a..a4fcdce 100644
--- a/mail-server/rspamd.nix
+++ b/mail-server/rspamd.nix
@@ -14,7 +14,12 @@
 #  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;
@@ -26,56 +31,74 @@ let
   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 ${cfg.dkimSelector}"
-    fi
-  '';
+  createDkimKeypair =
+    domain:
+    let
+      privateKey = "${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
+    '';
 in
 {
-  config = with cfg; lib.mkIf 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"
-      '')
-    ];
+  config =
+    with cfg;
+    lib.mkIf 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"
+          ''
+        )
+      ];
 
-    services.rspamd = {
-      enable = true;
-      inherit debug;
-      locals = {
-          "milter_headers.conf" = { text = ''
+      services.rspamd = {
+        enable = true;
+        inherit debug;
+        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 = ''
+            '';
+          };
+          "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 = ''
+            '';
+          };
+          "antivirus.conf" = lib.mkIf cfg.virusScanning {
+            text = ''
               clamav {
                 action = "reject";
                 symbol = "CLAM_VIRUS";
@@ -84,157 +107,168 @@ in
                 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}";
-            # Allow for usernames w/o domain part
-            allow_username_mismatch = true
-          ''; };
-          "dmarc.conf" = { text = ''
+            '';
+          };
+          "dkim_signing.conf" = {
+            text = ''
+              enabled = ${lib.boolToString cfg.dkimSigning};
+              path = "${cfg.dkimKeyDirectory}/$domain.$selector.key";
+              selector = "${cfg.dkimSelector}";
+              # Allow for usernames w/o domain part
+              allow_username_mismatch = true
+            '';
+          };
+          "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 != []) ''
-                  exclude_domains = ${builtins.toJSON cfg.dmarcReporting.excludeDomains};
-                ''}
-              }''}
-          ''; };
+                reporting {
+                  enabled = true;
+                  email = "${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 != [ ]) ''
+                    exclude_domains = ${builtins.toJSON cfg.dmarcReporting.excludeDomains};
+                  ''}
+                }''}
+            '';
+          };
+        };
+
+        workers.rspamd_proxy = {
+          type = "rspamd_proxy";
+          bindSockets = [
+            {
+              socket = "/run/rspamd/rspamd-milter.sock";
+              mode = "0664";
+            }
+          ];
+          count = 1; # Do not spawn too many processes of this type
+          extraConfig = ''
+            milter = yes; # Enable milter mode
+            timeout = 120s; # Needed for Milter usually
+
+            upstream "local" {
+              default = yes; # Self-scan upstreams are always default
+              self_scan = yes; # Enable self-scan
+            }
+          '';
+        };
+        workers.controller = {
+          type = "controller";
+          count = 1;
+          bindSockets = [
+            {
+              socket = "/run/rspamd/worker-controller.sock";
+              mode = "0666";
+            }
+          ];
+          includes = [ ];
+          extraConfig = ''
+            static_dir = "''${WWWDIR}"; # Serve the web UI static assets
+          '';
+        };
+
       };
 
-      workers.rspamd_proxy = {
-        type = "rspamd_proxy";
-        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
-          timeout = 120s; # Needed for Milter usually
+      services.redis.servers.rspamd.enable = lib.mkDefault true;
 
-          upstream "local" {
-            default = yes; # Self-scan upstreams are always default
-            self_scan = yes; # Enable self-scan
+      systemd.tmpfiles.settings."10-rspamd.conf" = {
+        "${cfg.dkimKeyDirectory}" = {
+          d = {
+            # Create /var/dkim owned by rspamd user/group
+            user = rspamdUser;
+            group = rspamdGroup;
+          };
+          Z = {
+            # Recursively adjust permissions in /var/dkim
+            user = rspamdUser;
+            group = rspamdGroup;
+          };
+        };
+      };
+
+      systemd.services.rspamd = {
+        requires = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
+        after = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
+        serviceConfig = lib.mkMerge [
+          {
+            SupplementaryGroups = [ config.services.redis.servers.rspamd.group ];
           }
-        '';
-      };
-      workers.controller = {
-        type = "controller";
-        count = 1;
-        bindSockets = [{
-          socket = "/run/rspamd/worker-controller.sock";
-          mode = "0666";
-        }];
-        includes = [];
-        extraConfig = ''
-          static_dir = "''${WWWDIR}"; # Serve the web UI static assets
-        '';
-      };
-
-    };
-
-    services.redis.servers.rspamd.enable = lib.mkDefault true;
-
-    systemd.tmpfiles.settings."10-rspamd.conf" = {
-      "${cfg.dkimKeyDirectory}" = {
-        d = {
-          # Create /var/dkim owned by rspamd user/group
-          user = rspamdUser;
-          group = rspamdGroup;
-        };
-        Z = {
-          # Recursively adjust permissions in /var/dkim
-          user = rspamdUser;
-          group = rspamdGroup;
-        };
-      };
-    };
-
-    systemd.services.rspamd = {
-      requires = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
-      after = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
-      serviceConfig = lib.mkMerge [
-        {
-          SupplementaryGroups = [ config.services.redis.servers.rspamd.group ];
-        }
-        (lib.optionalAttrs cfg.dkimSigning {
-          ExecStartPre = map createDkimKeypair cfg.domains;
-          ReadWritePaths = [ cfg.dkimKeyDirectory ];
-        })
-      ];
-    };
-
-    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 $(date -d "yesterday" "+%Y%m%d")
-      '';
-      serviceConfig = {
-        User = "${config.services.rspamd.user}";
-        Group = "${config.services.rspamd.group}";
-
-        AmbientCapabilities = [];
-        CapabilityBoundingSet = "";
-        DevicePolicy = "closed";
-        IPAddressAllow = "localhost";
-        LockPersonality = true;
-        NoNewPrivileges = true;
-        PrivateDevices = true;
-        PrivateMounts = true;
-        PrivateTmp = true;
-        PrivateUsers = true;
-        ProtectClock = true;
-        ProtectControlGroups = true;
-        ProtectHome = true;
-        ProtectHostname = true;
-        ProtectKernelLogs = true;
-        ProtectKernelModules = true;
-        ProtectKernelTunables = true;
-        ProtectProc = "invisible";
-        ProcSubset = "pid";
-        ProtectSystem = "strict";
-        RemoveIPC = true;
-        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
-        RestrictNamespaces = true;
-        RestrictRealtime = true;
-        RestrictSUIDSGID = true;
-        SystemCallArchitectures = "native";
-        SystemCallFilter = [
-          "@system-service"
-          "~@privileged"
+          (lib.optionalAttrs cfg.dkimSigning {
+            ExecStartPre = map createDkimKeypair cfg.domains;
+            ReadWritePaths = [ cfg.dkimKeyDirectory ];
+          })
         ];
-        UMask = "0077";
       };
-    };
 
-    systemd.timers.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
-      description = "Daily delivery of aggregated DMARC reports";
-      wantedBy = [
-        "timers.target"
-      ];
-      timerConfig = {
-        OnCalendar = "daily";
-        Persistent = true;
-        RandomizedDelaySec = 86400;
-        FixedRandomDelay = true;
+      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 $(date -d "yesterday" "+%Y%m%d")
+        '';
+        serviceConfig = {
+          User = "${config.services.rspamd.user}";
+          Group = "${config.services.rspamd.group}";
+
+          AmbientCapabilities = [ ];
+          CapabilityBoundingSet = "";
+          DevicePolicy = "closed";
+          IPAddressAllow = "localhost";
+          LockPersonality = true;
+          NoNewPrivileges = true;
+          PrivateDevices = true;
+          PrivateMounts = true;
+          PrivateTmp = true;
+          PrivateUsers = true;
+          ProtectClock = true;
+          ProtectControlGroups = true;
+          ProtectHome = true;
+          ProtectHostname = true;
+          ProtectKernelLogs = true;
+          ProtectKernelModules = true;
+          ProtectKernelTunables = true;
+          ProtectProc = "invisible";
+          ProcSubset = "pid";
+          ProtectSystem = "strict";
+          RemoveIPC = true;
+          RestrictAddressFamilies = [
+            "AF_INET"
+            "AF_INET6"
+          ];
+          RestrictNamespaces = true;
+          RestrictRealtime = true;
+          RestrictSUIDSGID = true;
+          SystemCallArchitectures = "native";
+          SystemCallFilter = [
+            "@system-service"
+            "~@privileged"
+          ];
+          UMask = "0077";
+        };
       };
-    };
 
-    systemd.services.postfix = {
-      after = [ rspamdSocket ];
-      requires = [ rspamdSocket ];
-    };
+      systemd.timers.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
+        description = "Daily delivery of aggregated DMARC reports";
+        wantedBy = [
+          "timers.target"
+        ];
+        timerConfig = {
+          OnCalendar = "daily";
+          Persistent = true;
+          RandomizedDelaySec = 86400;
+          FixedRandomDelay = true;
+        };
+      };
 
-    users.extraUsers.${postfixCfg.user}.extraGroups = [ rspamdCfg.group ];
-  };
+      systemd.services.postfix = {
+        after = [ rspamdSocket ];
+        requires = [ rspamdSocket ];
+      };
+
+      users.extraUsers.${postfixCfg.user}.extraGroups = [ rspamdCfg.group ];
+    };
 }
-
diff --git a/mail-server/systemd.nix b/mail-server/systemd.nix
index c411441..dd4bd63 100644
--- a/mail-server/systemd.nix
+++ b/mail-server/systemd.nix
@@ -14,72 +14,79 @@
 #  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;
   certificatesDeps =
     if cfg.certificateScheme == "manual" then
-      []
+      [ ]
     else if cfg.certificateScheme == "selfsigned" then
       [ "mailserver-selfsigned-certificate.service" ]
     else
       [ "acme-finished-${cfg.fqdn}.target" ];
 in
 {
-  config = with cfg; lib.mkIf enable {
-    # Create self signed certificate
-    systemd.services.mailserver-selfsigned-certificate = lib.mkIf (cfg.certificateScheme == "selfsigned") {
-      after = [ "local-fs.target" ];
-      script = ''
-        # Create certificates if they do not exist yet
-        dir="${cfg.certificateDirectory}"
-        fqdn="${cfg.fqdn}"
-        [[ $fqdn == /* ]] && fqdn=$(< "$fqdn")
-        key="$dir/key-${cfg.fqdn}.pem";
-        cert="$dir/cert-${cfg.fqdn}.pem";
+  config =
+    with cfg;
+    lib.mkIf enable {
+      # Create self signed certificate
+      systemd.services.mailserver-selfsigned-certificate =
+        lib.mkIf (cfg.certificateScheme == "selfsigned")
+          {
+            after = [ "local-fs.target" ];
+            script = ''
+              # Create certificates if they do not exist yet
+              dir="${cfg.certificateDirectory}"
+              fqdn="${cfg.fqdn}"
+              [[ $fqdn == /* ]] && fqdn=$(< "$fqdn")
+              key="$dir/key-${cfg.fqdn}.pem";
+              cert="$dir/cert-${cfg.fqdn}.pem";
 
-        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;
+              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}
+          '';
+      };
+
+      # 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";
       };
     };
-
-    # 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}
-      '';
-    };
-
-    # 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";
-    };
-  };
 }
diff --git a/mail-server/users.nix b/mail-server/users.nix
index bf654c3..e9af05a 100644
--- a/mail-server/users.nix
+++ b/mail-server/users.nix
@@ -14,7 +14,12 @@
 #  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,
+  ...
+}:
 
 with config.mailserver;
 
@@ -28,7 +33,6 @@ let
     group = vmailGroupName;
   };
 
-
   virtualMailUsersActivationScript = pkgs.writeScript "activate-virtual-mail-users" ''
     #!${pkgs.stdenv.shell}
 
@@ -46,28 +50,33 @@ let
 
     # 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))}
+    ${lib.concatMapStringsSep "\n" (
+      { name, sieveScript }:
+      if lib.isString sieveScript then
+        ''
+          if (! test -d "${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 {
+in
+{
   config = lib.mkIf enable {
     # assert that all accounts provide a password
     assertions = map (acct: {
@@ -76,15 +85,19 @@ in {
     }) (lib.attrValues loginAccounts);
 
     # 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 loginAccounts
+          )
+        );
 
     # set the vmail gid to a specific value
     users.groups = {
-      "${vmailGroupName}" = { gid = vmailUID; };
+      "${vmailGroupName}" = {
+        gid = vmailUID;
+      };
     };
 
     # define all users
diff --git a/shell.nix b/shell.nix
index 6234bb4..493783d 100644
--- a/shell.nix
+++ b/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
diff --git a/tests/clamav.nix b/tests/clamav.nix
index 19b799f..209e91e 100644
--- a/tests/clamav.nix
+++ b/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;
+
+          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!$H+H*";
+        };
+      };
+    client =
+      { nodes, pkgs, ... }:
+      let
         serverIP = nodes.server.networking.primaryIPAddress;
         clientIP = nodes.client.networking.primaryIPAddress;
         grep-ip = pkgs.writeScriptBin "grep-ip" ''
@@ -98,20 +104,25 @@
           echo grep '${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";
           };
@@ -185,59 +196,59 @@
           '';
         };
       };
-    };
+  };
 
   testScript = ''
-      start_all()
+    start_all()
 
-      server.wait_for_unit("multi-user.target")
-      client.wait_for_unit("multi-user.target")
+    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 ]"
-      )
+    # 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 ]"
+    )
 
-      client.execute("cp -p /etc/root/.* ~/")
-      client.succeed("mkdir -p ~/mail")
-      client.succeed("ls -la ~/ >&2")
-      client.succeed("cat ~/.fetchmailrc >&2")
-      client.succeed("cat ~/.procmailrc >&2")
-      client.succeed("cat ~/.msmtprc >&2")
+    client.execute("cp -p /etc/root/.* ~/")
+    client.succeed("mkdir -p ~/mail")
+    client.succeed("ls -la ~/ >&2")
+    client.succeed("cat ~/.fetchmailrc >&2")
+    client.succeed("cat ~/.procmailrc >&2")
+    client.succeed("cat ~/.msmtprc >&2")
 
-      # fetchmail returns EXIT_CODE 1 when no new mail
-      client.succeed("fetchmail --nosslcertck -v || [ $? -eq 1 ] >&2")
+    # fetchmail returns EXIT_CODE 1 when no new mail
+    client.succeed("fetchmail --nosslcertck -v || [ $? -eq 1 ] >&2")
 
-      # Verify that mail can be sent and received before testing virus scanner
-      client.execute("rm ~/mail/*")
-      client.succeed("msmtp -a user2 user1@example.com < /etc/root/safe-email >&2")
-      # give the mail server some time to process the mail
-      server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-      client.execute("rm ~/mail/*")
-      # fetchmail returns EXIT_CODE 0 when it retrieves mail
-      client.succeed("fetchmail --nosslcertck -v >&2")
-      client.execute("rm ~/mail/*")
+    # Verify that mail can be sent and received before testing virus scanner
+    client.execute("rm ~/mail/*")
+    client.succeed("msmtp -a user2 user1@example.com < /etc/root/safe-email >&2")
+    # give the mail server some time to process the mail
+    server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+    client.execute("rm ~/mail/*")
+    # fetchmail returns EXIT_CODE 0 when it retrieves mail
+    client.succeed("fetchmail --nosslcertck -v >&2")
+    client.execute("rm ~/mail/*")
 
-      with subtest("virus scan file"):
-          server.succeed(
-              'set +o pipefail; clamdscan $(readlink -f /etc/root/eicar.com.txt) | grep "Txt\\.Malware\\.Agent-1787597 FOUND" >&2'
-          )
+    with subtest("virus scan file"):
+        server.succeed(
+            'set +o pipefail; clamdscan $(readlink -f /etc/root/eicar.com.txt) | grep "Txt\\.Malware\\.Agent-1787597 FOUND" >&2'
+        )
 
-      with subtest("virus scan email"):
-          client.succeed(
-              'set +o pipefail; msmtp -a user2 user1@example.com < /etc/root/virus-email 2>&1 | tee /dev/stderr | grep "server message: 554 5\\.7\\.1" >&2'
-          )
-          server.succeed("journalctl -u rspamd | grep -i eicar")
-          # give the mail server some time to process the mail
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+    with subtest("virus scan email"):
+        client.succeed(
+            'set +o pipefail; msmtp -a user2 user1@example.com < /etc/root/virus-email 2>&1 | tee /dev/stderr | grep "server message: 554 5\\.7\\.1" >&2'
+        )
+        server.succeed("journalctl -u rspamd | grep -i eicar")
+        # give the mail server some time to process the mail
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
 
-      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")
-    '';
+    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")
+  '';
 }
diff --git a/tests/external.nix b/tests/external.nix
index a65f0ce..82abb65 100644
--- a/tests/external.nix
+++ b/tests/external.nix
@@ -18,74 +18,84 @@
   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 ];
 
-            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 = 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";
+          };
+        };
+      };
+    client =
+      { nodes, pkgs, ... }:
+      let
         serverIP = nodes.server.networking.primaryIPAddress;
         clientIP = nodes.client.networking.primaryIPAddress;
         grep-ip = pkgs.writeScriptBin "grep-ip" ''
@@ -172,27 +182,36 @@
             assert needle in repr(response)
             imap.close()
         '';
-      in {
+      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";
           };
@@ -338,176 +357,176 @@
           '';
         };
       };
-    };
+  };
 
   testScript = ''
-      start_all()
+    start_all()
 
-      server.wait_for_unit("multi-user.target")
-      client.wait_for_unit("multi-user.target")
+    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 ]"
-      )
+    # 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 ]"
+    )
 
-      client.execute("cp -p /etc/root/.* ~/")
-      client.succeed("mkdir -p ~/mail")
-      client.succeed("ls -la ~/ >&2")
-      client.succeed("cat ~/.fetchmailrc >&2")
-      client.succeed("cat ~/.procmailrc >&2")
-      client.succeed("cat ~/.msmtprc >&2")
+    client.execute("cp -p /etc/root/.* ~/")
+    client.succeed("mkdir -p ~/mail")
+    client.succeed("ls -la ~/ >&2")
+    client.succeed("cat ~/.fetchmailrc >&2")
+    client.succeed("cat ~/.procmailrc >&2")
+    client.succeed("cat ~/.msmtprc >&2")
 
-      with subtest("imap retrieving mail"):
-          # fetchmail returns EXIT_CODE 1 when no new mail
-          client.succeed("fetchmail --nosslcertck -v || [ $? -eq 1 ] >&2")
+    with subtest("imap retrieving mail"):
+        # fetchmail returns EXIT_CODE 1 when no new mail
+        client.succeed("fetchmail --nosslcertck -v || [ $? -eq 1 ] >&2")
 
-      with subtest("submission port send mail"):
-          # send email from user2 to user1
-          client.succeed(
-              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email1 >&2"
-          )
-          # give the mail server some time to process the mail
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+    with subtest("submission port send mail"):
+        # send email from user2 to user1
+        client.succeed(
+            "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email1 >&2"
+        )
+        # give the mail server some time to process the mail
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
 
-      with subtest("imap retrieving mail 2"):
-          client.execute("rm ~/mail/*")
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail --nosslcertck -v >&2")
+    with subtest("imap retrieving mail 2"):
+        client.execute("rm ~/mail/*")
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail --nosslcertck -v >&2")
 
-      with subtest("remove sensitive information on submission port"):
-          client.succeed("cat ~/mail/* >&2")
-          ## make sure our IP is _not_ in the email header
-          client.fail("grep-ip ~/mail/*")
-          client.succeed("check-mail-id ~/mail/*")
+    with subtest("remove sensitive information on submission port"):
+        client.succeed("cat ~/mail/* >&2")
+        ## make sure our IP is _not_ in the email header
+        client.fail("grep-ip ~/mail/*")
+        client.succeed("check-mail-id ~/mail/*")
 
-      with subtest("have correct fqdn as sender"):
-          client.succeed("grep 'Received: from mail.example.com' ~/mail/*")
+    with subtest("have correct fqdn as sender"):
+        client.succeed("grep 'Received: from mail.example.com' ~/mail/*")
 
-      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'"
-          )
+    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'"
+        )
 
-      with subtest("dkim singing, multiple domains"):
-          client.execute("rm ~/mail/*")
-          # send email from user2 to user1
-          client.succeed(
-              "msmtp -a test2 --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email2 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail  --nosslcertck -v")
-          client.succeed("cat ~/mail/* >&2")
-          # make sure it is dkim signed
-          client.succeed("grep DKIM-Signature: ~/mail/*")
+    with subtest("dkim singing, multiple domains"):
+        client.execute("rm ~/mail/*")
+        # send email from user2 to user1
+        client.succeed(
+            "msmtp -a test2 --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email2 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail  --nosslcertck -v")
+        client.succeed("cat ~/mail/* >&2")
+        # make sure it is dkim signed
+        client.succeed("grep DKIM-Signature: ~/mail/*")
 
-      with subtest("aliases"):
-          client.execute("rm ~/mail/*")
-          # send email from chuck to postmaster
-          client.succeed(
-              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on postmaster@example.com < /etc/root/email2 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail --nosslcertck -v")
+    with subtest("aliases"):
+        client.execute("rm ~/mail/*")
+        # send email from chuck to postmaster
+        client.succeed(
+            "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on postmaster@example.com < /etc/root/email2 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail --nosslcertck -v")
 
-      with subtest("catchAlls"):
-          client.execute("rm ~/mail/*")
-          # send email from chuck to non exsitent account
-          client.succeed(
-              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lol@example.com < /etc/root/email2 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail --nosslcertck -v")
+    with subtest("catchAlls"):
+        client.execute("rm ~/mail/*")
+        # send email from chuck to non exsitent account
+        client.succeed(
+            "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lol@example.com < /etc/root/email2 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail --nosslcertck -v")
 
-          client.execute("rm ~/mail/*")
-          # send email from user1 to chuck
-          client.succeed(
-              "msmtp -a test4 --tls=on --tls-certcheck=off --auth=on chuck@example.com < /etc/root/email2 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 1 when no new mail
-          # if this succeeds, it means that user1 recieved the mail that was intended for chuck.
-          client.fail("fetchmail --nosslcertck -v")
+        client.execute("rm ~/mail/*")
+        # send email from user1 to chuck
+        client.succeed(
+            "msmtp -a test4 --tls=on --tls-certcheck=off --auth=on chuck@example.com < /etc/root/email2 >&2"
+        )
+        server.wait_until_fails('[ "$(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.
+        client.fail("fetchmail --nosslcertck -v")
 
-      with subtest("extraVirtualAliases"):
-          client.execute("rm ~/mail/*")
-          # send email from single-alias to user1
-          client.succeed(
-              "msmtp -a test5 --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email4 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail --nosslcertck -v")
+    with subtest("extraVirtualAliases"):
+        client.execute("rm ~/mail/*")
+        # send email from single-alias to user1
+        client.succeed(
+            "msmtp -a test5 --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email4 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail --nosslcertck -v")
 
-          client.execute("rm ~/mail/*")
-          # send email from user1 to multi-alias (user{1,2}@example.com)
-          client.succeed(
-              "msmtp -a test --tls=on --tls-certcheck=off --auth=on multi-alias@example.com < /etc/root/email5 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.succeed("fetchmail --nosslcertck -v")
+        client.execute("rm ~/mail/*")
+        # send email from user1 to multi-alias (user{1,2}@example.com)
+        client.succeed(
+            "msmtp -a test --tls=on --tls-certcheck=off --auth=on multi-alias@example.com < /etc/root/email5 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.succeed("fetchmail --nosslcertck -v")
 
-      with subtest("quota"):
-          client.execute("rm ~/mail/*")
-          client.execute("mv ~/.fetchmailRcLowQuota ~/.fetchmailrc")
+    with subtest("quota"):
+        client.execute("rm ~/mail/*")
+        client.execute("mv ~/.fetchmailRcLowQuota ~/.fetchmailrc")
 
-          client.succeed(
-              "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lowquota@example.com < /etc/root/email2 >&2"
-          )
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
-          # fetchmail returns EXIT_CODE 0 when it retrieves mail
-          client.fail("fetchmail --nosslcertck -v")
+        client.succeed(
+            "msmtp -a test3 --tls=on --tls-certcheck=off --auth=on lowquota@example.com < /etc/root/email2 >&2"
+        )
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+        # fetchmail returns EXIT_CODE 0 when it retrieves mail
+        client.fail("fetchmail --nosslcertck -v")
 
-      with subtest("imap sieve junk trainer"):
-          # send email from user2 to user1
-          client.succeed(
-              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email1 >&2"
-          )
-          # give the mail server some time to process the mail
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+    with subtest("imap sieve junk trainer"):
+        # send email from user2 to user1
+        client.succeed(
+            "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email1 >&2"
+        )
+        # give the mail server some time to process the mail
+        server.wait_until_fails('[ "$(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")
-          client.succeed("imap-mark-ham >&2")
-          server.wait_until_succeeds("journalctl -u dovecot2 | grep -i rspamd-learn-ham.sh >&2")
+        client.succeed("imap-mark-spam >&2")
+        server.wait_until_succeeds("journalctl -u dovecot2 | 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")
 
-      with subtest("full text search and indexation"):
-          # send 2 email from user2 to user1
-          client.succeed(
-              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email6 >&2"
-          )
-          client.succeed(
-              "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email7 >&2"
-          )
-          # give the mail server some time to process the mail
-          server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
+    with subtest("full text search and indexation"):
+        # send 2 email from user2 to user1
+        client.succeed(
+            "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email6 >&2"
+        )
+        client.succeed(
+            "msmtp -a test --tls=on --tls-certcheck=off --auth=on user1@example.com < /etc/root/email7 >&2"
+        )
+        # give the mail server some time to process the mail
+        server.wait_until_fails('[ "$(postqueue -p)" != "Mail queue is empty" ]')
 
-          # should find exactly one email containing this
-          client.succeed("search INBOX 576a4565b70f5a4c1a0925cabdb587a6 >&2")
-          # 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")
-          # check that Junk is not indexed
-          server.fail("journalctl -u dovecot2 | grep 'fts-flatcurve(JUNK): Indexing ' >&2")
+        # should find exactly one email containing this
+        client.succeed("search INBOX 576a4565b70f5a4c1a0925cabdb587a6 >&2")
+        # 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")
+        # check that Junk is not indexed
+        server.fail("journalctl -u dovecot2 | grep 'fts-flatcurve(JUNK): Indexing ' >&2")
 
-      with subtest("dmarc reporting"):
-          server.systemctl("start rspamd-dmarc-reporter.service")
+    with subtest("dmarc reporting"):
+        server.systemctl("start rspamd-dmarc-reporter.service")
 
-      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")
-          # harmless ? https://dovecot.org/pipermail/dovecot/2020-August/119575.html
-          server.fail(
-            "journalctl -u dovecot2 | \
-              grep -v 'Expunged message reappeared, giving a new UID' | \
-              grep -v 'Time moved forwards' | \
-              grep -i warning >&2"
-          )
-    '';
+    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")
+        # harmless ? https://dovecot.org/pipermail/dovecot/2020-August/119575.html
+        server.fail(
+          "journalctl -u dovecot2 | \
+            grep -v 'Expunged message reappeared, giving a new UID' | \
+            grep -v 'Time moved forwards' | \
+            grep -i warning >&2"
+        )
+  '';
 }
diff --git a/tests/internal.nix b/tests/internal.nix
index 8f47e70..af552c3 100644
--- a/tests/internal.nix
+++ b/tests/internal.nix
@@ -30,11 +30,16 @@ 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 -sm bcrypt <<<"$password" > $out
+      '';
 
   hashedPasswordFile = hashPassword "my-password";
   passwordFile = pkgs.writeText "password" "my-password";
@@ -43,55 +48,62 @@ in
   name = "internal";
 
   nodes = {
-    machine = { pkgs, ... }: {
-      imports = [
-        ./../default.nix
-        ./lib/config.nix
-      ];
+    machine =
+      { pkgs, ... }:
+      {
+        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;
+        mailserver = {
+          enable = true;
+          fqdn = "mail.example.com";
+          domains = [
+            "example.com"
+            "domain.com"
+          ];
+          localDnsResolver = false;
 
-        loginAccounts = {
-          "user1@example.com" = {
-            hashedPasswordFile = hashedPasswordFile;
+          loginAccounts = {
+            "user1@example.com" = {
+              hashedPasswordFile = hashedPasswordFile;
+            };
+            "user2@example.com" = {
+              hashedPasswordFile = hashedPasswordFile;
+              aliasesRegexp = [ ''/^user2.*@domain\.com$/'' ];
+            };
+            "send-only@example.com" = {
+              hashedPasswordFile = hashPassword "send-only";
+              sendOnly = true;
+            };
           };
-          "user2@example.com" = {
-            hashedPasswordFile = hashedPasswordFile;
-            aliasesRegexp = [''/^user2.*@domain\.com$/''];
-          };
-          "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";
           };
+
+          vmailGroupName = "vmail";
+          vmailUID = 5000;
+
+          enableImap = false;
         };
-        forwards = {
-          # user2@example.com is a local account and its mails are
-          # also forwarded to user1@example.com
-          "user2@example.com" = "user1@example.com";
-        };
-
-        vmailGroupName = "vmail";
-        vmailUID = 5000;
-
-        enableImap = false;
       };
-    };
   };
   testScript = ''
     machine.start()
diff --git a/tests/ldap.nix b/tests/ldap.nix
index 8187d7d..1c92572 100644
--- a/tests/ldap.nix
+++ b/tests/ldap.nix
@@ -7,110 +7,113 @@ in
   name = "ldap";
 
   nodes = {
-    machine = { pkgs, ... }: {
-      imports = [
-        ./../default.nix
-        ./lib/config.nix
-      ];
+    machine =
+      { pkgs, ... }:
+      {
+        imports = [
+          ./../default.nix
+          ./lib/config.nix
+        ];
 
-      virtualisation.memorySize = 1024;
+        virtualisation.memorySize = 1024;
 
-      services.openssh = {
-        enable = true;
-        settings.PermitRootLogin = "yes";
-      };
+        services.openssh = {
+          enable = true;
+          settings.PermitRootLogin = "yes";
+        };
 
-      environment.systemPackages = [
-        (pkgs.writeScriptBin "mail-check" ''
-          ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
-        '')];
+        environment.systemPackages = [
+          (pkgs.writeScriptBin "mail-check" ''
+            ${pkgs.python3}/bin/python ${../scripts/mail-check.py} $@
+          '')
+        ];
 
-      environment.etc.bind-password.text = bindPassword;
+        environment.etc.bind-password.text = bindPassword;
 
-      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";
+        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" = ''
+            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}
+          '';
         };
-        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 = {
+        mailserver = {
           enable = true;
-          uris = [
-            "ldap://"
-          ];
-          bind = {
-            dn = "cn=mail,dc=example";
-            passwordFile = "/etc/bind-password";
+          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";
           };
-          searchBase = "ou=users,dc=example";
-          searchScope = "sub";
+
+          forwards = {
+            "bob_fw@example.com" = "bob@example.com";
+          };
+
+          vmailGroupName = "vmail";
+          vmailUID = 5000;
+
+          enableImap = false;
         };
-
-        forwards = {
-          "bob_fw@example.com" = "bob@example.com";
-        };
-
-        vmailGroupName = "vmail";
-        vmailUID = 5000;
-
-        enableImap = false;
       };
-    };
   };
   testScript = ''
     import sys
diff --git a/tests/multiple.nix b/tests/multiple.nix
index 3e71cd6..2c6d0fc 100644
--- a/tests/multiple.nix
+++ b/tests/multiple.nix
@@ -6,16 +6,23 @@
 }:
 
 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
       '';
 
-    password = pkgs.writeText "password" "password";
+  password = pkgs.writeText "password" "password";
 
-    domainGenerator = domain: { pkgs, ... }: {
+  domainGenerator =
+    domain:
+    { pkgs, ... }:
+    {
       imports = [
         ../default.nix
         ./lib/config.nix
@@ -37,7 +44,10 @@ 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"
+        ];
       };
     };
 
@@ -47,23 +57,34 @@ 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()