Win98SE Internet Connection sharing

I have PDC and other servers running on the real IPs. I recently used one machine for sharing internet connection with others computer. The PDC is now still on the outside and none of the client can log in. I added another NIC and assigned to the internal ips, but still doesn’t work nor seeing other computer on the network neighborhood. How do I make the best so that I can have client use the resource of the server as well?