anchor.diff:  
         port = mkOption {
           default = 14311;
  -        type = types.int;
  +        type = types.port;
           description = "Specify port to listen on.";
         }; # qserve.port
   
  
positive.code: 
        port = mkOption {
          default = 8899;
          type = types.int;
          description = "Specify port to listen on.";
        }; # nserve.port
  
  
negative.code: 
              port = mkOption {
                default = 8898;
                type = types.port;
                description = "Port to listen to when serving files from cache.";
              }; # nslave.http.port
  
  