Merge branch 'master' of github.com:r-raymond/nixos-mailserver

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true

.travis.yml

@@ -1,6 +1,5 @@
 language: nix
 script:
-    - git clone --depth 1 https://github.com/NixOS/nixpkgs ../nixpkgs
     - nix-build tests/intern.nix
     - nix-build tests/extern.nix
 

README.md

@@ -1,5 +1,6 @@
 # ![Simple Nixos MailServer][logo]
 ![license](https://img.shields.io/badge/license-GPL3-brightgreen.svg)
+![status](https://travis-ci.org/r-raymond/nixos-mailserver.svg?branch=master)
 
 
 ## Stable Releases
@@ -9,7 +10,8 @@ None so far.
 [Latest Release Candidate](https://github.com/r-raymond/nixos-mailserver/releases/latest)
 
 ## Features
-### v1.1
+### v2.0
+ * [x] Multiple Domains
  * Postfix MTA
     - [x] smtp on port 25
     - [x] submission port 587
@@ -21,6 +23,7 @@ None so far.
  * Certificates
     - [x] manual certificates
     - [x] on the fly creation
+    - [x] Let's Encrypt
  * Spam Filtering
     - [x] via rspamd
     - [x] hard coded sieve script to move spam into Junk folder
@@ -32,17 +35,13 @@ None so far.
     - [x] declarative user management
     - [x] declarative password management
 
-
+### In the future
-### v1.2
-  * Certificates
-    - [ ] Let's Encrypt
   * Sieves
     - [ ] Allow user defined sieve scripts
   * User Aliases
     - [ ] More complete alias support
-
+  * DKIM Signing
-### v2.0
+    - [ ] Allow a per domain selector
-  * [ ] Multiple Domains
 
 ### Changelog
 
@@ -50,6 +49,45 @@ None so far.
  * Changed structure to Nix Modules
  * Adds Sieve support
 
+#### v1.1 -> v2.0
+ * rename domain to fqdn, seperate fqdn from domains
+ * multi domain support
+
+### How to Deploy
+
+```nix
+{ config, pkgs, ... }:
+{
+  imports = [
+    (builtins.fetchTarball "https://github.com/r-raymond/nixos-mailserver/releases/tag/v2.0-rc1")
+  ];
+
+  mailserver = {
+    enable = true;
+    fqdn = "mail.example.com";
+    domains = [ "example.com" "example2.com" ];
+    loginAccounts = {
+        "user1@example.com" = {
+            hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
+        };
+    };
+    virtualAliases = {
+        # address = forward address;
+        "info@example.com" = "user1@example.com";
+        "postmaster@example.com" = "user1@example.com";
+        "abuse@example.com" = "user1@example.com";
+        "user1@example2.com" = "user1@example.com";
+        "info@example2.com" = "user1@example.com";
+        "postmaster@example2.com" = "user1@example.com";
+        "abuse@example2.com" = "user1@example.com";
+    };
+  };
+}
+```
+
+For a complete list of options, see `default.nix`.
+
+
 ### How to Test
 
 You can test the setup via `nixops`. After installation, do
@@ -73,6 +111,52 @@ openssl s_client -host mail.example.com -port 143 -starttls imap
 ```
 
 
+## How to Set Up a 10/10 Mail Server
+Mail servers can be a tricky thing to set up. This guide is supposed to run you
+through the most important steps to achieve a 10/10 score on `mail-tester.com`.
+
+### Fully Qualified Domain Name
+No matter how many domains you want to serve on your mail server, you need to
+settle on a _Fully Qualified Domain Name_ (FQDN) where your server is reachable,
+so that other servers can find yours. Common FQDN include `mx.example.com`
+(where `example.com` is a domain you own) or `mail.example.com`.
+
+After you settled on a FQDN (we will assume `mx.example.com` henceforth) you
+need to
+  * Set a DNS entry on your domain to point to the IP of the server. For this
+    add a DNS record such as
+
+    | Name (Subdomain) | TTL   | Type | Priority | Value             |
+    | ---------------- | ----- | ---- | -------- | ----------------- |
+    | mx.example.com   | 10800 | A    |          | `xxx.xxx.xxx.xxx` |
+
+    to your domain, where `xxx.xxx.xxx.xxx` is the IP of your server.
+
+  * Set a `rDNS` (reverse DNS) entry for your FQDN. You need to do so wherever
+    you have rented your server. Make sure that `xxx.xxx.xxx.xxx` resolves to
+    `mx.example.com`.
+
+
+### MX Record
+
+| Name (Subdomain) | TTL   | Type | Priority | Value             |
+| ---------------- | ----- | ---- | -------- | ----------------- |
+| domain1.com      |       | MX   | 10       | mx.exmaple.com    |
+
+### Spf record
+
+| Name (Subdomain) | TTL   | Type | Priority | Value                             |
+| ---------------- | ----- | ---- | -------- | -----------------                 |
+| domain1.com      | 10800 | TXT  |          | `v=spf1 ip4:xxx.xxx.xxx.xxx -all` |
+
+### DKIM signature
+
+| Name (Subdomain)            | TTL   | Type | Priority | Value                     |
+| ----------------            | ----- | ---- | -------- | -----------------         |
+| dkim._domainkey.domain1.com | 10800 | TXT  |          | `v=DKIM1; p=yyyyyyyyyyyy` |
+
+where `yyyyyyyyyyyy` is the `DKIM` signature
+
 ## A Complete Mail Server Without Moving Parts
 
 ### Used Technologies
@@ -87,7 +171,7 @@ openssl s_client -host mail.example.com -port 143 -starttls imap
  * Pam
 
 ### Features
- * one domain
+ * unlimited domain
  * unlimited mail accounts
  * unlimited aliases for every mail account
  * spam and virus checking
@@ -104,8 +188,10 @@ openssl s_client -host mail.example.com -port 143 -starttls imap
 
 ## Contributors
  * Special thanks to @Infinisil for the module rewrite
+ * Special thanks to @jbboehr for multidomain implementation
  * @danbst
  * @phdoerfler
+ * @eqyiel
 
 
 ### Credits

default.nix

@@ -26,19 +26,17 @@ in
   options.mailserver = {
     enable = mkEnableOption "nixos-mailserver";
 
-    domain = mkOption {
+    fqdn = mkOption {
       type = types.str;
       example = "example.com";
-      description = "The domain that this mail server serves. So far only one domain is supported";
+      description = "The fully qualified domain name of the mail server.";
     };
 
-    hostPrefix = mkOption {
+    domains = mkOption {
-      type = types.str;
+      type = types.listOf types.str;
-      default = "mail";
+      example = [ "example.com" ];
-      description = ''
+      default = [];
-        The prefix of the FQDN of the server. In this example the FQDN of the server
+      description = "The domains that this mail server serves.";
-        is given by 'mail.example.com'
-      '';
     };
 
     loginAccounts = mkOption {
@@ -113,7 +111,7 @@ in
 
     vmailUserName = mkOption {
       type = types.str;
-      default = "vmail";
+      default = "virtualMail";
       description = ''
         The user name and group name of the user that owns the directory where all
         the mail is stored.
@@ -122,7 +120,7 @@ in
 
     vmailGroupName = mkOption {
       type = types.str;
-      default = "vmail";
+      default = "virtualMail";
       description = ''
         The user name and group name of the user that owns the directory where all
         the mail is stored.
@@ -138,7 +136,7 @@ in
     };
 
     certificateScheme = mkOption {
-      type = types.enum [ 1 2 ];
+      type = types.enum [ 1 2 3 ];
       default = 2;
       description = ''
         Certificate Files. There are three options for these.
@@ -149,8 +147,6 @@ in
            this implies that a stripped down webserver has to be started. This also
            implies that the FQDN must be set as an `A` record to point to the IP of
            the server. TODO: Explain more details
-
-        TODO: Only certificate scheme 1) and 2) work as of yet.
       '';
     };
 
@@ -188,7 +184,7 @@ in
       default = true;
       description = ''
         Whether to enable imap / pop3. Both variants are only supported in the
-        (sane) startTLS configuration. (TODO: Allow SSL ports). The ports are
+        (sane) startTLS configuration. The ports are
 
         110 - Pop3
         143 - IMAP
@@ -196,12 +192,21 @@ in
       '';
     };
 
+    enableImapSsl = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to enable IMAPS, setting this option to true will open port 993
+        in the firewall.
+      '';
+    };
+
     enablePop3 = mkOption {
       type = types.bool;
       default = false;
       description = ''
-        Whether to enable POP3. Both variants are only supported in the
+        Whether to enable POP3. Both variants are only supported in the (sane)
-        (sane) startTLS configuration. (TODO: Allow SSL ports). The ports are
+        startTLS configuration. The ports are
 
         110 - Pop3
         143 - IMAP
@@ -209,8 +214,14 @@ in
       '';
     };
 
-    # imapSsl = mkOption {} #< TODO
+    enablePop3Ssl = mkOption {
-    # pop3Ssl = mkOption {} #< TODO
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to enable POP3S, setting this option to true will open port 995
+        in the firewall.
+      '';
+    };
 
     virusScanning = mkOption {
       type = types.bool;
@@ -256,5 +267,6 @@ in
     ./mail-server/dovecot.nix
     ./mail-server/postfix.nix
     ./mail-server/rmilter.nix
+    ./mail-server/nginx.nix
   ];
 }

mail-server/common.nix

@@ -24,13 +24,17 @@ in
   certificatePath = if cfg.certificateScheme == 1
              then cfg.certificateFile
              else if cfg.certificateScheme == 2
-                  then "${cfg.certificateDirectory}/cert-${cfg.domain}.pem"
+                  then "${cfg.certificateDirectory}/cert-${cfg.fqdn}.pem"
-                  else "";
+                  else if cfg.certificateScheme == 3
+                       then "/var/lib/acme/${cfg.fqdn}/fullchain.pem"
+                       else throw "Error: Certificate Scheme must be in { 1, 2, 3 }";
 
   # key :: PATH
   keyPath = if cfg.certificateScheme == 1
         then cfg.keyFile
         else if cfg.certificateScheme == 2
-             then "${cfg.certificateDirectory}/key-${cfg.domain}.pem"
+             then "${cfg.certificateDirectory}/key-${cfg.fqdn}.pem"
-             else "";
+              else if cfg.certificateScheme == 3
+                   then "/var/lib/acme/${cfg.fqdn}/key.pem"
+                   else throw "Error: Certificate Scheme must be in { 1, 2, 3 }";
 }

mail-server/networking.nix

@@ -24,8 +24,10 @@ in
 
     networking.firewall = {
       allowedTCPPorts = [ 25 587 ]
-        ++ (if enableImap then [ 143 ] else [])
+        ++ lib.optional enableImap 143
-        ++ (if enablePop3 then [ 110 ] else []);
+        ++ lib.optional enableImapSsl 993
+        ++ lib.optional enablePop3 110
+        ++ lib.optional enablePop3Ssl 995;
     };
   };
 }

mail-server/nginx.nix

@@ -0,0 +1,48 @@
+#  nixos-mailserver: a simple mail server
+#  Copyright (C) 2016-2017  Robin Raymond
+#
+#  This program is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program. If not, see <http://www.gnu.org/licenses/>
+
+
+{ config, pkgs, lib, ... }:
+
+with (import ./common.nix { inherit config; });
+
+let
+  cfg = config.mailserver;
+  acmeRoot = "/var/lib/acme/acme-challenge";
+in
+{
+  config = lib.mkIf (cfg.certificateScheme == 3) {
+    services.nginx = {
+      enable = true;
+      virtualHosts."${cfg.fqdn}" = {
+        serverName = cfg.fqdn;
+        forceSSL = true;
+        enableACME = true;
+        acmeRoot = acmeRoot;
+      };
+    };
+    security.acme.certs."${cfg.fqdn}".postRun = #{
+ #     domain = "${cfg.fqdn}";
+#      webroot = acmeRoot;
+#      postRun = 
+      ''
+        systemctl reload nginx
+        systemctl reload postfix
+        systemctl reload dovecot2
+      '';
+#    };
+  };
+}

mail-server/postfix.nix

@@ -19,17 +19,18 @@
 with (import ./common.nix { inherit config; });
 
 let
+  inherit (lib.strings) concatStringsSep;
   cfg = config.mailserver;
 
   # valiases_postfix :: [ String ]
   valiases_postfix = map
     (from:
       let to = cfg.virtualAliases.${from};
-      in "${from}@${cfg.domain} ${to}@${cfg.domain}")
+      in "${from} ${to}")
     (builtins.attrNames cfg.virtualAliases);
 
   # accountToIdentity :: User -> String
-  accountToIdentity = account: "${account.name}@${cfg.domain} ${account.name}@${cfg.domain}";
+  accountToIdentity = account: "${account.name} ${account.name}";
 
   # vaccounts_identity :: [ String ]
   vaccounts_identity = map accountToIdentity (lib.attrValues cfg.loginAccounts);
@@ -38,7 +39,7 @@ let
   valiases_file = builtins.toFile "valias" (lib.concatStringsSep "\n" valiases_postfix);
 
   # vhosts_file :: Path
-  vhosts_file = builtins.toFile "vhosts" cfg.domain;
+  vhosts_file = builtins.toFile "vhosts" (concatStringsSep "\n" cfg.domains);
 
   # vaccounts_file :: Path
   # see
@@ -49,9 +50,9 @@ let
   vaccounts_file = builtins.toFile "vaccounts" (lib.concatStringsSep "\n" (vaccounts_identity ++ valiases_postfix));
 
   submissionHeaderCleanupRules = pkgs.writeText "submission_header_cleanup_rules" ''
-     ### Removes sensitive headers from mails handed in via the submission port.
+     # Removes sensitive headers from mails handed in via the submission port.
-     ### See https://thomas-leister.de/mailserver-debian-stretch/
+     # See https://thomas-leister.de/mailserver-debian-stretch/
-     ### Uses "pcre" style regex.
+     # Uses "pcre" style regex.
 
      /^Received:/            IGNORE
      /^X-Originating-IP:/    IGNORE
@@ -76,7 +77,7 @@ in
       ''
         # Extra Config
 
-        smtpd_banner = $myhostname ESMTP NO UCE
+        smtpd_banner = ${fqdn} ESMTP NO UCE
         disable_vrfy_command = yes
         message_size_limit = 20971520
 

mail-server/rmilter.nix

@@ -28,6 +28,8 @@ let
            ''
            else "";
   dkim = if cfg.dkimSigning
+  # Note: domain = "*"; causes Rmilter to try to search key in the key path
+  # as keypath/domain.selector.key for any domain.
          then
          ''
             dkim {

mail-server/services.nix

@@ -24,14 +24,14 @@ let
   cert = if cfg.certificateScheme == 1
          then cfg.certificateFile
          else if cfg.certificateScheme == 2
-              then "${cfg.certificateDirectory}/cert-${cfg.domain}.pem"
+              then "${cfg.certificateDirectory}/cert-${cfg.fqdn.pem"
               else "";
 
   # key :: PATH
   key = if cfg.certificateScheme == 1
         then cfg.keyFile
         else if cfg.certificateScheme == 2
-             then "${cfg.certificateDirectory}/key-${cfg.domain}.pem"
+             then "${cfg.certificateDirectory}/key-${cfg.fqdn}.pem"
              else "";
 in
 {

mail-server/systemd.nix

@@ -23,10 +23,10 @@ let
         ''
           # Create certificates if they do not exist yet
           dir="${cfg.certificateDirectory}"
-          fqdn="${cfg.hostPrefix}.${cfg.domain}"
+          fqdn="${cfg.fqdn}"
           case $fqdn in /*) fqdn=$(cat "$fqdn");; esac
-          key="''${dir}/key-${cfg.domain}.pem";
+          key="''${dir}/key-${cfg.fqdn}.pem";
-          cert="''${dir}/cert-${cfg.domain}.pem";
+          cert="''${dir}/cert-${cfg.fqdn}.pem";
 
           if [ ! -f "''${key}" ] || [ ! -f "''${cert}" ]
           then
@@ -38,22 +38,31 @@ let
         ''
         else "";
 
-  dkim_key = "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.private";
+  createDomainDkimCert = dom:
-  dkim_txt = "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.txt";
+    let
+      dkim_key = "${cfg.dkimKeyDirectory}/${dom}.${cfg.dkimSelector}.key";
+      dkim_txt = "${cfg.dkimKeyDirectory}/${dom}.${cfg.dkimSelector}.txt";
+    in
+        ''
+          if [ ! -f "${dkim_key}" ] || [ ! -f "${dkim_txt}" ]
+          then
+              ${pkgs.opendkim}/bin/opendkim-genkey -s "${cfg.dkimSelector}" \
+                                                   -d "${dom}" \
+                                                   --directory="${cfg.dkimKeyDirectory}"
+              mv "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.private" "${dkim_key}"
+              mv "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.txt" "${dkim_txt}"
+          fi
+        '';
+  createAllCerts = lib.concatStringsSep "\n" (map createDomainDkimCert cfg.domains);
   create_dkim_cert =
         ''
           # Create dkim dir
           mkdir -p "${cfg.dkimKeyDirectory}"
           chown rmilter:rmilter "${cfg.dkimKeyDirectory}"
 
-          if [ ! -f "${dkim_key}" ] || [ ! -f "${dkim_txt}" ]
+          ${createAllCerts}
-          then
 
-              ${pkgs.opendkim}/bin/opendkim-genkey -s "${cfg.dkimSelector}" \
+          chown -R rmilter:rmilter "${cfg.dkimKeyDirectory}"
-                                                   -d ${cfg.domain} \
-                                                   --directory="${cfg.dkimKeyDirectory}"
-              chown rmilter:rmilter "${dkim_key}"
-          fi
         '';
 in
 {
@@ -63,6 +72,7 @@ in
 
     # Create certificates and maildir folder
     systemd.services.postfix = {
+      after = (if (certificateScheme == 3) then [ "nginx.service" ] else []);
       preStart =
       ''
       # Create mail directory and set permissions. See

mail-server/users.nix

@@ -19,25 +19,26 @@
 with config.mailserver;
 
 let
-  vmail_user = [{
+  vmail_user = {
-    #name = vmailUserName;
+    name = vmailUserName;
     isNormalUser = false;
     uid = vmailUIDStart;
     home = mailDirectory;
     createHome = true;
-    #group = vmailGroupName;
+    group = vmailGroupName;
-  }];
+  };
 
   # accountsToUser :: String -> UserRecord
   accountsToUser = account: {
-    name = account.name + "@" + domain;
+    name = account.name;
     isNormalUser = false;
     group = vmailGroupName;
     inherit (account) hashedPassword;
   };
 
-  # mail_user :: [ UserRecord ]
+  # mail_users :: { [String]: UserRecord }
-  mail_user = map accountsToUser (lib.attrValues loginAccounts);
+  mail_users = lib.foldl (prev: next: prev // { "${next.name}" = next; }) {}
+    (map accountsToUser (lib.attrValues loginAccounts));
 
 in
 {
@@ -45,10 +46,12 @@ in
   config = lib.mkIf enable {
     # set the vmail gid to a specific value
     users.groups = {
-      vmail = { gid = vmailUIDStart; };
+      "${vmailGroupName}" = { gid = vmailUIDStart; };
     };
 
     # define all users
-    users.extraUsers = vmail_user ++ mail_user;
+    users.users = mail_users // {
+      "${vmail_user.name}" = lib.mkForce vmail_user;
+    };
   };
 }

nixops/single-server.nix

@@ -10,18 +10,21 @@
 
         mailserver = {
           enable = true;
-          domain = "example.com";
+          fqdn = "mail.example.com";
-
+          domains = [ "example.com" "example2.com" ];
-          hostPrefix = "mail";
           loginAccounts = {
-              user1 = {
+              "user1@example.com" = {
                   hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
               };
           };
           virtualAliases = {
-              info = "user1";
+              "info@example.com" = "user1@example.com";
-              postmaster = "user1";
+              "postmaster@example.com" = "user1@example.com";
-              abuse = "user1";
+              "abuse@example.com" = "user1@example.com";
+              "user1@example2.com" = "user1@example.com";
+              "info@example2.com" = "user1@example.com";
+              "postmaster@example2.com" = "user1@example.com";
+              "abuse@example2.com" = "user1@example.com";
           };
         };
     };

tests/extern.nix

@@ -14,7 +14,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-import ./../../nixpkgs/nixos/tests/make-test.nix {
+import <nixpkgs/nixos/tests/make-test.nix> {
 
   nodes =
     { server = { config, pkgs, ... }:
@@ -25,14 +25,17 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
 
             mailserver = {
               enable = true;
-              domain = "example.com";
+              fqdn = "mail.example.com";
+              domains = [ "example.com" "example2.com" ];
 
-              hostPrefix = "mail";
               loginAccounts = {
-                  user1 = {
+                  "user1@example.com" = {
                       hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
                   };
-                  user2 = {
+                  "user2@example.com" = {
+                      hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
+                  };
+                  "user@example2.com" = {
                       hashedPassword = "$6$u61JrAtuI0a$nGEEfTP5.eefxoScUGVG/Tl0alqla2aGax4oTd85v3j3xSmhv/02gNfSemv/aaMinlv9j/ZABosVKBrRvN5Qv0";
                   };
               };
@@ -68,6 +71,13 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
         from           user2\@example.com
         user           user2\@example.com
         password       user2
+
+        account        test2
+        host           SERVER
+        port           587
+        from           user\@example2.com
+        user           user\@example2.com
+        password       user2
     '';
     email1 =
     ''
@@ -82,6 +92,21 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
 
         how are you doing today?
     '';
+    email2 =
+    ''
+        From: User <user\@example2.com>
+        To: User1 <user1\@example.com>
+        Cc:
+        Bcc:
+        Subject: This is a test Email from user\@example2.com to user1
+        Reply-To:
+
+        Hello User1,
+
+        how are you doing today?
+
+        XOXO User1
+    '';
   in
     ''
       startAll;
@@ -121,5 +146,19 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
         # make sure our IP is _not_ in the email header
         $client->fail("grep `ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print \$2}' | cut -f1  -d'/'` ~/mail/*");
       };
+
+      subtest "dkim singing, multiple domains", sub {
+          $client->succeed("rm ~/mail/*");
+          $client->succeed("rm mail.txt");
+          $client->succeed("echo '${email2}' > mail.txt");
+          # send email from user2 to user1
+          $client->succeed("msmtp -a test2 --tls=on --tls-certcheck=off --auth=on user1\@example.com < mail.txt >&2");
+          $client->succeed("sleep 5");
+          # fetchmail returns EXIT_CODE 0 when it retrieves mail
+          $client->succeed("fetchmail -v");
+          $client->succeed("cat ~/mail/* >&2");
+          # make sure it is dkim signed
+          $client->succeed("grep DKIM ~/mail/*");
+      };
     '';
 }

tests/intern.nix

@@ -14,7 +14,7 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-import ./../../nixpkgs/nixos/tests/make-test.nix {
+import <nixpkgs/nixos/tests/make-test.nix> {
 
   machine =
     { config, pkgs, ... }:
@@ -25,14 +25,17 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
 
         mailserver = {
           enable = true;
-          domain = "example.com";
+          fqdn = "mail.example.com";
+          domains = [ "example.com" ];
 
-          hostPrefix = "mail";
           loginAccounts = {
-              user1 = {
+              "user1@example.com" = {
                   hashedPassword = "$6$/z4n8AQl6K$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/";
               };
           };
+
+          vmailGroupName = "vmail";
+          vmailUIDStart = 5000;
         };
     };
 
@@ -49,5 +52,9 @@ import ./../../nixpkgs/nixos/tests/make-test.nix {
             $machine->succeed("cat /etc/shadow | grep 'user1\@example.com:\$6\$/z4n8AQl6K\$kiOkBTWlZfBd7PvF5GsJ8PmPgdZsFGN1jPGZufxxr60PoR0oUsrvzm2oQiflyz5ir9fFJ.d/zKm/NgLXNUsNX/:1::::::'");
       };
 
+      subtest "vmail gid is set correctly", sub {
+            $machine->succeed("getent group vmail | grep 5000");
+      };
+
     '';
 }