We have a Windows domain network with 2 Hyper-V hosts. On these hosts, there are several Hyper-V VM clients. Two of these clients are Domain Controllers.
The Hyper-V hosts are both clients of that domain. This brings one to a common time synchronization issue, as the hosts will try to sync their time with the PDC emulator and the domain controllers sync their time with the Hyper-V host.
While working on that issue, I didn't realize that the firewall in the network does not allow outgoing traffic on port 123. Which lead to several (failed) reconfiguration attempts.
Switching the time source
Once the problem was understood, I set the hosts up to sync to a reliable, on-site time source and wanted the DCs to simply use the VM IC Time Synchronization Provider again (so that they would sync the time with the host).
But one of the DCs is refusing to switch to the VM IC Time Synchronization Provider, it still uses the Local CMS Clock source (which, to my understanding, is not desirable).
What failed so far?
I tried disabling the Time Synchronization component for that VM in the Hyper-V Manager, then rebooting the machine, restarting the w32time service a couple of times, re-enabling the Time Synchronization component. That didn't work. I also tried other permutations of this process that didn't help either.
I tried changing the
Enabledvalues in the registry (
HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders) for the different time providers.
I re-installed the Hyper-V integration package in the client.