Bizarre Network Problem

Hello
Bizzare Problem with internet access on a LAN.
I was ask to help setup 3 workstations to access the internet via a DSL connection which was preexisting. The network had a Windows 2000 server setup as a domain controller which could successfully get out on the internet. 3 workstations logged on to this DC. The problem is that after several hours of troubleshooting, this is as far as I got.
As long as the DC was not pulled into the switch all workstation and my laptop could get on the net. The DSL modem/router has DHCP/Nat active.
But when I put the DC back on the switch then only it can get out. Even if the workstations and my laptop were in workgroup mode. I even set IP parameters static. I can ping the router but not WAN when the server is plugged into the switch. I tried IP numbers and well as URL. (Not DNS I would guess)
I have made sure that DHCP,DNS etc. was off on the server as well.
Any help is greatly appreciated!!!

 

I'll take a stab and say IIS is running on the DC?

I ran into this years ago (when win2k was new) but my old head doesnt remember that far back.

On the Client: Check tools / internet options / Connection Tab / Lan settings / and see if a proxi has been installed.

Look for the installation of the IIS cleint on the workstation.


What were you trying to ping on the WAN side?
Have you verified your source will respond to ping traffic?