Quick question, since I don't have time to figure it out myself, does Minecraft use udp, tcp or both? Please refresh my memory
I think it only uses TCP Source: http://getsatisfaction.com/mojang/topics/use_udp_instead_of_tcp - It is 12 months old though, but there are still people replying to it now. I'll look into it a bit further and see if I can get a clearer answer.
RCON is remote console (TCP) Notch added a seperate query protocol as well. http://dinnerbone.com/blog/2011/10/14/minecraft-19-has-rcon-and-query/ More on query: http://wiki.vg/Query