figuring out ip with airport/router

another question for my bro:

Hey,
i am trying to run a hotline/kdx server from one of my machines over an
aiport network connected through a cable modem. I think there are settings
i need to configure to distribute ips, or maybe not, but i am not sure how
to reach the computer from the internet from another machine. Any experts
(or even non-experts) on aiport settings/wireless protocols that have a clue
would be great....

thanks!

feel free to email me if you have info as i may be unable to check/post here.... hossler@gelbin.org