Linux game server

Lets start with specs. Mandrake 8.1, SOHOware broadguard router/hub(latest firmware. The linux box has static IP which I have DMZ host open for that IP and have also experimented with port forwarding for the game port. The game by the way the Half life DoD mod. The problem: All the status on the server says it is running fine. However I cannot see it from either the Inet or my internal network. I am new to Linux and I think I may have missed something on the linux box. Would love help on this. If anyone has a DoD server running on linux…HELP!! 🙂