Posted by damcatlady (Ranked 2 on Scrabble (GameSpy) Ladder) on April 05, 2013 at 15:09:14 PDT:
In Windows Firewall, you need to have the following TCP and UDP ports open in order to be able to launch and play, (if you are having trouble doing so):
6667 (IRC)
3783 (Voice Chat Port)
27900 (Master Server UDP Heartbeat)
28900 (Master Server List Request)
29900 (GP Connection Manager)
29901 (GP Search Manager)
13139 (Custom UDP Pings)
6515 (Dplay UDP)
6500 (Query Port)