confusing ping behavior with new kernel.

Hi, I just built a new machine. It has a built in sis900 lan and I have a ne2000-pci second lan in there. Upon booting with the default 2.4-4GB kernel. both cards are found and are pingable, so I know things work. I made a kernel from vanilla sources, a 2.4-13 kernel, and the lan cards are found at boot, I can dial out and ping over ppp0, but pinging my localhost, 192.168.0.1, or 192.168.0.4 just hangs. ?????????? What did I do wrong? It is perplexing that the stock suse kernel works the pinging just fine. Is there some patch which suse applies which I may be unaware of? It is a K7S5A motherboard with the sis chipset. Any clues? Thanks.