After reading the post, it sounds like the network is going 'one-way.' Can he transfer files between each computer? Or is it just an internet problem? A shot in the dark might be to make sure the Access Control tab is clicked on Share Level Access (in Client for Microsoft Networks). I had a problem where my network appeared to be working fine in one direction (I could transfer files from my WinXP to my Win98 PC, but not the other way around.). I did not have problems with Internet sharing however.
Here's a shot in the dark: could it be that the router is maintaing an ARP table and see's a different MAC address with the same IP and won't respond to it? Have you tried setting the W2K box up as .3 ?
<i>It's always the one thing you never suspected.</i>
Not sure if the spec on the website is up to date, but the latest firmware has included a firewall as well as the NAT, so you can disable the NAT and still have some security. At the moment NAT is enabled and the firewall is disabled.
I decided to try loading W98SE onto the system and if I got my ping, to try and get a W2K upgrade to install onto it.
Couldn't get the W98SE install to ping either. Damn. What's more the NIC was causing sluggish behaviour on startup, and on shutdowns & restarts, I had to use the reset button.
Decided the NIC <b>must</b> be dodgy, and it should be replaced. Just for fun, I tried moving it from PCI slot 5 to PCI slot 4, as slot 4 seems to have less (none in fact) BIOS allocated resources. Slot 5 has connections with the HPT370 controller etc. Back to the IRQ stuff here.
Well anyway, it worked!!! Slot 4 it remains and I have W98SE & W2K running fine.
Many thanks to all for your help in trouble shooting this one. I did have a hunch on the IRQs, but having no real experience with W2K's handling of shared resources, I was operating a bit in the dark.