I installed SP4 on my Win2k Member Server. Now I can not connect to MSN for Windows updates and I can't connect to network associates for my virus protection updates. When I say can't connect, It just slowly clocks and never completes. What is interesting is that I can connect to my ISP, bank, and school, but the response time is extremely slow!
The machine experienced a memory dump last night so I booted to the last know good configuration. Also, my router light is showing plenty of activity and the other '98 machines are able to connect no problem with excellent response times. Is my machine just destined for a full OS re-install?
I'd recommend rolling back to SP3 (you did install SP4 with the ability to roll back, right?) and seeing if that improves anything. It sounds like a problem described in Q224829, regarding RFC1323 (long fat pipes) support. Make the changes listed there regarding the Tcp1323Opts registry key (set it to 0) and see if that helps.
This was first published in April 2004