anchor.diff:          pkgs.openresolv
         ]
         ++ optional (cfg.bridges != {}) pkgs.bridge_utils
  +      ++ optional hasVirtuals pkgs.tunctl
         ++ optional cfg.enableIPv6 pkgs.ndisc6;
   
       security.setuidPrograms = [ "ping" "ping6" ];
  
positive.code: let
  
    cfg = config.networking;
  
  in
  
  
negative.code: 
    config = {
  
      boot.kernelModules = optional cfg.enableIPv6 "ipv6" ++ optional hasVirtuals "tun";
  
      environment.systemPackages =
        [ pkgs.host
  