82579LM goes through constant connect/disconnect cycle
After looking at all the unresolved posts concerning the problems people experienced with the 82579LM and 82569V embedded NICs, I am not sure if adding yet another discussion on this topic will be productive, but here goes. I have several hundred Dell Optiplex 990s in my environment that use the 82579LM for network connectivity. Every desktop uses 802.1x authentication as a requirement to gain network access. Sporadically, a random user will report that their network connection is lost. The symptoms are always the same: the NIC attempts and appears to successfully pass 802.1x authentication, tries and fails to obtain an IP address, gets 169.254.x.x instead, and then reports that the link is "disconnected". This all happens in a couple of seconds and then repeats endlessly. All troubleshooting efforts have failed. The only thing that resolves the issue is a reboot.
Troubleshooting-wise, I have tried the following:
1) Re-seat the network connection
2) Swap patch cables
3) Disable/enable the NIC
4) Update the NIC driver with Intel's latest driver
5) Completely uninstall old NIC driver before installing latest Intel driver
6) Reset the network stack (netsh int ip reset)
The frustrating thing about this issue is that I haven't been able to find anything that might point to the root cause since it happens so intermittently and randomly. Dell support has been useless, of course. At this point, what I would really like to do, instead of just trying different things in the dark, is to gain some insight into what would cause the NIC to go through these disconnect/reconnect cycles. Is there a utility or a way to capture the NIC's state or what it's doing when the problem is occurring? And what is being cleared on a reboot that brings back normal operation?
If any Intel engineers are reading this, I would appreciate your feedback because I'm at my wit's end.