diff --git a/mail-config.nix b/mail-config.nix
index 3629a1f..7541065 100644
--- a/mail-config.nix
+++ b/mail-config.nix
@@ -58,11 +58,7 @@ in
     inherit domain host_prefix;
   };
 
-  # TODO: Move to /mail-server/systemd.nix
-  # TODO: Respect setting of maildir
-  # Set the correct permissions for dovecot vmail folder. See
-  # <http://wiki2.dovecot.org/SharedMailboxes/Permissions>. We choose
-  # to use the systemd service to set the folder permissions whenever
-  # dovecot gets started.
-  systemd.services.dovecot2.preStart = "chmod 02770 /var/vmail";
+  systemd = import ./mail-server/systemd.nix {
+    inherit mail_dir;
+  };
 }
diff --git a/mail-server/systemd.nix b/mail-server/systemd.nix
new file mode 100644
index 0000000..61767fa
--- /dev/null
+++ b/mail-server/systemd.nix
@@ -0,0 +1,25 @@
+#  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/>
+
+{ mail_dir }:
+
+{
+  # Set the correct permissions for dovecot vmail folder. See
+  # <http://wiki2.dovecot.org/SharedMailboxes/Permissions>. We choose
+  # to use the systemd service to set the folder permissions whenever
+  # dovecot gets started.
+  services.dovecot2.preStart = ("mkdir -p " + mail_dir + "; chmod 02770 " + mail_dir);
+}