diff --git a/nixos/modules/mail.nix b/nixos/modules/mail.nix
index 94cfae6..62fe93a 100644
--- a/nixos/modules/mail.nix
+++ b/nixos/modules/mail.nix
@@ -159,6 +159,21 @@ in {
             ];
           };
 
+          session.ehlo.require = [
+            {
+              "if" = "starts_with(remote_ip, '192.168.0.')"; #TODO setup vms properly
+              "then" = false;
+            }
+            {"else" = true;}
+          ];
+          session.ehlo.reject-non-fqdn = [
+            {
+              "if" = "starts_with(remote_ip, '192.168.0.')"; #TODO setup vms properly
+              "then" = false;
+            }
+            {"else" = true;}
+          ];
+
           # Stalwart gets its configuration from two places: A TOML configuration file that we control in this module
           # and from a database that can be configured from web management interface or via Rest API.
           # We here define what comes from the TOML-file and especially add "sieve.trusted.scripts.*" to the default ones