Yeah you guessed correct. Its a LAN dod server and the firewall is a separate box.
The client does use a fixed portnumber because when they try to connect, they connect with this: myexternalip:27015
Also, I have two nics, eth0 going to the internal LAN, and eth1 going to my ADSL modem. When I connect to the ISP it creates the ppp0 virtual device...should i put ppp0 in the rules or eth1? or doesn't it really matter?
I don't know anything about the protcols that DOD uses either...thats why i put both UDP and TCP in, just incase
Ill try out your rules tonight...thats for the help