Windows 2012R2 Hyper-V server randomly loses access to the Internet, but not LAN RRS feed

  • Question

  • A client has a Windows 2012 R2 server running Hyper-V, with two VMs on it.  One VM is fine, but the other one, which is accessed from the outside world, keeps randomly losing internet access without a (noticeable) cause or pattern, or even error message.

    When the server does drop its internet connectivity, I can remote into the host to investigate.  The host is fine, the other VM is fine, but the problem server just doesn't want to seem to connect to the internet.  It can resolve outside addresses without issue, but not reach them.  I can resolve, but not ping it.  I can ping another local server on the LAN without issue.  Running a tracert to results in nothing coming back at all, tracert to anything else (on the LAN) comes back with one hop without issue.

    Running the network troubleshooter results in a message that the destination server is not responding, so it seems as if the problem is not Windows itself.

    Malware / virus scan turned up nothing, and running "netsh winsock reset catalog" does not resolve it, either.

    While it's possible this could be a Router / Firewall issue outside the server, it's odd that it is only happening to this one VM, and not the other, or the host server.

    Any clue what may be causing this, or how to troubleshoot further?

    Friday, November 10, 2017 8:50 PM