NT routing troubles #2

I have a NT 4.0 server connected to the internet via cable modem.One network card ip 192.168.24.1 is connected to my internal network, the second nic with ip 208.x.x.x is connected to the internet. I have ip fowarding turned on and from a NT workstation I can ping the external interface of my NT server, but I can’t ping my isp or anything else. How can I set it up so I can foward all of the traffic on my local lan or from my proxy server for the internet to my NT server.