No internet connection after moving from direct connect DSL to router

My XP-SP2 machine was directly connected to a DSL modem and everything worked. Then I put a linksys WRT45G router in-between the computer and the DSL modem and the internet connection stopped working. However, I have a different XP-SP2 machine that works fine behind the router (it was never direct connected to the DSL modem).

-The router is not the problem, my other XP-SP2 machine works fine, the "internet gateway" is automatically configured (in the network connections), DHCP brings in the gateway / DNS addresses just fine. I can ping and traceroute from within the router diagnostics no problem.

- On the machine that doesn't work, DHCP DOES work perfectly, the DNS/Gateway addrs are brought in just fine, the "ipconfig /all" output is basically identical to the working machine.

- On the broken machine I cannot ping the default gateway addr nor the DNS addrs, all I can ping in the router at 192.168.1.1

- On the broken machine, the "internet gateway" is NOT configured automatically (there is no manual config that I can find?). I don't know if this is the problem or not because I do not understand what the darn "internet gateway" is and why we need it (is it me, or is MS obscuring things??)

- I checked for the "uPnP" stuff, it is all there identical to the working machine. It is enabled also on the router.

- I have installed the latest versions of the NIC driver (Realtek 8xxx) and the linksys firmware, no dice. There were some other problems with the NIC that were fixed by the new driver (didnt work when running at 10 Mpb/s), but not this issue.

I am at the end of the line here... I highly suspect this is an issue with the computer's drivers or config, the router and DSL all seem fine (the other machine works great!!). I have alot of experience making and testing networks, so this simple issue is really driving me mad, and I feel like windows in all it's attempts to simply things really only obscures the important details making it harder to diagnose these kind of issues.

Any help is appreciated!!

-Rob

 

Worth a try on the problem machine to reset networking to the defaults and set things up from there. From a cmd prompt

Code:

Netsh int ip reset C:\iplog.txt

If that doesn't fix things post back and we can at least start trying to fix the beast from a known set of values on the PC.

The text file created will contain details about the things that the netsh reset changed so might be interesting for you to have a look at.