internet games hosting

One of the folks on my network wants to host battlestar galatcia
games...

I the router for the network (all machines connect off of it) uses
iptables.

Previously, I used a linksys befw11s4 router, which had a dmz host
option. The computer used to host battlestar games was specified, and
everything was fine.

However, i don't know how to do the equivalent (or better yet, just
allow requests to join the games through) with iptables. I'd rather not
do DMZ host, since it will totally expose the one computer, but i don't
think the battlestar ports are always the same...

Anyone have any experience in using iptables to allow hosting games over
the internet? Obviously, it doesn't have to be battlestar specific...

And how does the dmz hosting work? Are all ports just forwarded to the
dmz host machine? I thought so, but other port forwarding wasn't broken
when this was enabled... I guess order of precedence? Port forwarding
rules applied then everything else goes to the dmz host?


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Thanks