[expert] Connection sharing and 2 Nics ?

[|nSaNe]

Hiya,   I have Internet connection sharing set up for my windows PC's and have recently brought Xbox live, now if i use a dediacated cat5 lead to the mandrake box it works fine (after editing shorewall rules to allow ports) however as I am cheap and have had the same network in place for years my home PC network is coax and therefore I cant use this with my Xbox.   So i thought it would be easier and cheaper to just add another nic to the linux server and use hat to server for Xbox live.   now my question is, when i set up internet connections sharing in mandrake it only allows me to select one nic for usevia (i presume) the dhcp server, and I need both (or a workaround as i can manually set ip's on the xbox) to get this to work,   Any help would be apreciated, i changed from a 2k server to this a few months ago and have been happy so far, I would know how to do this in 2k server, but in linux I am stuck, so if anyone can tell me how to get the second nic to work with internet connection sharing (or even better the dhcp server to work also with it) I would be in debt to you.   Thanks for reading   Lee Wilson     Nb.sorry if this has been sent twice, my ISP mail server is playing up and I am unsure if it went the first time.