You're assuming that most NATted jj2 servers have their port 10053 forwarded. I see a major firewall problem here. Personally I would go for an existing TCP port i.e. 10052 as most servers have that forwarded. Since plus is already capable of native packet inspection, you can design a new packet that houses all the query packets inside. Since non-plus servers won't recognize this packet, they will simply drop it. You can wrap an existing standard packets in a shell pretty easily, all you do is attach two bytes at the beginning of a packet - packet size and a new "query" packet ID.


Also, the idea of having the server display ping of its clients (like in many other games) would be neat.