All IP traffic gets dropped after a while

Question

I'm on a Windows Server 2003 machine, and after some light to moderate network use, the server occasionally drops all IP traffic. It takes a while to get into this state, and there's nothing obvious that triggers it. It's possible to get the server out of this state by terminating (cleanly or abruptly) or restarting any applications that [believe that they] still have TCP connections open. The server in question becomes unreachable to the rest of the network and it is unable to reach the rest of the network, so the upstream gateway is not involved.

What IP traffic have I observed dropping? TCP, UDP, ICMP.

What kinds of applications are running? Typical workstation (Terminal Server) workloads.

Is there a firewall running? Yes, Windows Firewall. Disabling Windows Firewall after the problem occurs has no effect.

Is there an AV program running? Yes, McAfee VirusScan Enterprise. Disabling VirusScan after the problem occurs has no effect.

So, wizards, how does one trace the path for IP datagrams heading through the layers of the network stack to the bitbucket?

Answer 1

After noticing some stutter in real-time audio playback, I found a very high amount of CPU time being spent on DPCs on my system along with a high number of interrupts. I used DPC Latency Checker to view the current DPC latency and started attempting to disable non-critical drivers, one-by-one. Upon disabling both Intel PRO/1000 EB Network Connection devices on the platform, I saw the DPC latency drop back down to reasonable levels -- and audio playback stopped stuttering! I uninstalled and updated the Intel PRO/1000 driver and now both the audio playback stuttering and the dropped connections have since stopped decreased in frequency.

Since the previous driver I was using had worked fine for a few years, and uninstalling and updating resolved the problem, I can only hypothesize that there must have been some persistent settings that were causing the problem and that have now been cleaned up.