Windows 2012R2 VMhost lost connectivity to network

I installed a Windows 2012R2 server and it has four hosts on it.

Today everything was working fine like the last thirty 30days and the file server lost connectivity to the network. I could log onto the VM through 2012 the domain password work.

I could not ping the gateway nor out the network through the file server.

Clients could not ping the file server.

The other three VM's could ping the gateway and they could ping out side the network.

I re-booted the whole file server and once the the re-boot was complete. I started the file server VM. It came backup and and I could ping the gateway and out side and clients could connect to it again.

The other three came up just fine and work as expected.

Is there a patch that needs to applied to the Windows 2012R for this.

This is a Windows 2012R2 Dell T630 with 96 Gigs of Ram.

Thanks very much for the help!

Check this update list
Check this update list

Like you this has happened to me and just like you it has happened very infrequently. And just like you I was able to resolve the issue by rebooting the Hyper-V )physical) server and that fixed all the issues. I did not have to reboot my VM clients though just Hyper-V. I have been unable to find a cause and since it is so infrequent it has been tough to pin down. Fortunately it has only happened to me maybe once in the last 6 to 9 months. Did you find any clues in the event logs at the time this happened, I know there was nothing in mine?

No nothing in the logs it just quit working, but there maybe a rollup that may fix it I will have to do some digging.


If you are sure it is not a bad cable, or a bad port on your switch/router or maybe a loss of power you may want to request attention to your questions for other experts as I don't know what else to suggest.


After getting feedback, this is what I did; called Dell and applied a firmware fix to the the network adapter and BIOS. Software update for network driver on the server. Dell also made a few tweaks to the Hyper2012R2 the network had not dropped since.

I also did a Firmware update to the HP switches they were two version in the wind. I looked at what HP said about the firmware for the switches, but only said it was a bug fix. After I applied that, the switches seemed faster. The network moves better. If anybody else is in this situation look for firmware and software updates that might need to be applied. It maybe too soon to tell if that was the problem, but I am betting it is.

Thanks for the help!


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