This is a known issue - this may be a fix.
From one of the developers:
Quote:
Guys, big favour to ask,
It seems the dlink router may be causing some problems, disconnecting people between maps. Some users have reportedly fixed the problem by removing T:V from the router's DMZ.
If you have a dlink router you can help make sure this really is the problem in two ways;
1) If you regularly get disconnected between maps, try removing T:V from the router's DMZ. See if the problem disappears.
2) If you don't get regularly disconnected, and your DMZ is off, turn it on and see if the problem manifests itself.
Post here with your findings, including the model of your router and your system specs.
Cheers!