Need help blocking all ports except a few

[Sommarnatt <sommarnatt@nwn.se>]

Hi!

I'm new to iptables/chains and need help setting up my new Debian system.
The system is going to be a gameserver and I've never set that up before.

The only services that really need to be open are ssh2 and the game server.

The game server needs these ports opened:
5120-5300 (UDP only)
6667, 80,27900,28900,29900.29901,13139 and 6500

Any takers? Or some pointers? Tried Firehol, but it complains that it needs a 
kernel higher than 2.3

Kind Regards,
Sommarnatt