diff --git a/sys/mailserver/default.nix b/sys/mailserver/default.nix
index 46a013a..9906806 100644
--- a/sys/mailserver/default.nix
+++ b/sys/mailserver/default.nix
@@ -1,7 +1,7 @@
 { config, pkgs, ... }:
 {
   imports = [
-    /etc/nixos/vpsadminos.nix
+    ./vpsadminos.nix
   ];
 
   services.openssh.enable = true;
diff --git a/sys/mailserver/vpsadminos.nix b/sys/mailserver/vpsadminos.nix
new file mode 100644
index 0000000..070017e
--- /dev/null
+++ b/sys/mailserver/vpsadminos.nix
@@ -0,0 +1,67 @@
+# This file provides compatibility for NixOS to run in a container on vpsAdminOS
+# hosts.
+#
+# If you're experiencing issues, try updating this file to the latest version
+# from vpsAdminOS repository:
+#
+#   https://github.com/vpsfreecz/vpsadminos/blob/staging/os/lib/nixos-container/vpsadminos.nix
+
+{ config, pkgs, lib, ... }:
+with lib;
+let
+  nameservers = [
+    "1.1.1.1"
+    "2606:4700:4700::1111"
+  ];
+in {
+  networking.nameservers = mkDefault nameservers;
+  services.resolved = mkDefault { fallbackDns = nameservers; };
+  networking.dhcpcd.extraConfig = "noipv4ll";
+
+  systemd.services.systemd-sysctl.enable = false;
+  systemd.services.systemd-oomd.enable = false;
+  systemd.sockets."systemd-journald-audit".enable = false;
+  systemd.mounts = [ {where = "/sys/kernel/debug"; enable = false;} ];
+  systemd.services.rpc-gssd.enable = false;
+
+  # Due to our restrictions in /sys, the default systemd-udev-trigger fails
+  # on accessing PCI devices, etc. Override it to match only network devices.
+  # In addition, boot.isContainer prevents systemd-udev-trigger.service from
+  # being enabled at all, so add it explicitly.
+  systemd.additionalUpstreamSystemUnits = [
+    "systemd-udev-trigger.service"
+  ];
+  systemd.services.systemd-udev-trigger.serviceConfig.ExecStart = [
+    ""
+    "-udevadm trigger --subsystem-match=net --action=add"
+  ];
+
+  boot.isContainer = true;
+  boot.enableContainers = mkDefault true;
+  boot.loader.initScript.enable = true;
+  boot.specialFileSystems."/run/keys".fsType = mkForce "tmpfs";
+  boot.systemdExecutable = mkDefault "/run/current-system/systemd/lib/systemd/systemd systemd.unified_cgroup_hierarchy=0";
+
+  # Overrides for <nixpkgs/nixos/modules/virtualisation/container-config.nix>
+  documentation.enable = mkOverride 500 true;
+  documentation.nixos.enable = mkOverride 500 true;
+  networking.useHostResolvConf = mkOverride 500 false;
+  services.openssh.startWhenNeeded = mkOverride 500 false;
+
+  # Bring up the network, /ifcfg.{add,del} are supplied by the vpsAdminOS host
+  systemd.services.networking-setup = {
+    description = "Load network configuration provided by the vpsAdminOS host";
+    before = [ "network.target" ];
+    wantedBy = [ "network.target" ];
+    after = [ "network-pre.target" ];
+    path = [ pkgs.iproute2 ];
+    serviceConfig = {
+      Type = "oneshot";
+      RemainAfterExit = true;
+      ExecStart = "${pkgs.bash}/bin/bash /ifcfg.add";
+      ExecStop = "${pkgs.bash}/bin/bash /ifcfg.del";
+    };
+    unitConfig.ConditionPathExists = "/ifcfg.add";
+    restartIfChanged = false;
+  };
+}