I ran into an issue recently where servers that have been running for 6+ months with normal patching/rebooting, but without issue, all of a sudden started losing network connectivity. The icon would pop up in the tray and the server was no longer reachable. I still don’t know the underlying cause of the issue, but here’s what I figured out.
Thanks to this blog post, I was able to throw some commands at the box (network tuning stuff) and determine which specific command fixed the network access.
Here are the commands:
netsh int tcp set global chimney=Disabled
netsh int tcp set global autotuninglevel=normal
netsh int tcp set supplemental custom congestionprovider=none
netsh int tcp set global ecncapability=Disabled
netsh int ip set global taskoffload=disabled
netsh int tcp set global timestamps=Disabled
netsh int tcp set global RSS=Enable
netsh int tcp set global rsc=disabled
The supplemental custom command didn’t work for some reason, but the winner here was to enable RSS on the network interface.
Hope this helps.