anchor.diff:          default = {};
           type = with types; loaOf (submodule (
             { name, config, ... }: {
  -            options = commonTunOpts name;
  +            options = {
  +              destinationPort = mkOption {
  +                type = types.int;
  +                default = 0;
  +                description = "Connect to particular port at destination.";
  +              };
  +            } // commonTunOpts name;
               config = {
                 name = mkDefault name;
               };
  
positive.code:       '')
      }
      ${flip concatMapStrings
        (collect (tun: tun ? port && tun ? host) cfg.inTunnels)
        (tun: let portStr = toString tun.port; in ''
          [${tun.name}]
          type = server
          destination = ${tun.destination}
          keys = ${tun.keys}
          host = ${tun.address}
          port = ${tun.port}
          inport = ${tun.inPort}
          accesslist = ${builtins.concatStringsSep "," tun.accessList}
        '')
      }
  
negative.code:         [${tun.name}]
          type = client
          destination = ${tun.destination}
          destinationport = ${toString tun.destinationPort}
          keys = ${tun.keys}
          address = ${tun.address}
          port = ${toString tun.port}
  