Q. If i am running a UT server behind a firewall, which ports do i need to open? 
A. Firstly, the UT server needs to be able to listen to the TCP port which you have selected
 (if any) for your web admin port. It will also need to listen to several UDP ports and they are
 not always the same because they depend on which port you have selected for your game port.

 If you have selected 7777 as your game port (this is the default) then your server will want to
 listen to UDP ports 7777, 7778, 7779, 7780, and 7781. And, finally, UDP port 9999 is required for
 outgoing UDP traffic to the ngWorldStats site and UDP port 27900 is required for outgoing UDP
 traffic to the master server.