add vm working with dhcp+dns

nixos/modules/networking/dmz/default.nix

@@ -23,7 +23,8 @@ in
   config = lib.mkIf cfg.enable {
     lab.networking.allowDMZConnectivity = true;
 
-    networking.firewall.interfaces.${config.lab.networking.dmzBridgeName} = {
+    # TODO: listen only on dmz interface, make this portable between physical and VM.
+    networking.firewall = {
       allowedTCPPorts = [ 53 5353 ];
       allowedUDPPorts = [ 53 67 5353 ];
     };