In order to test some trial software under good conditions -- that is, not a race against the clock, I wanted to isolate an HyperV virtual machine. This is in no way to promote piracy or something, just peace of mind. I'll eventually buy the software. This being said, here is how I did:
- Forbid internet access to the VM. This is easy with DD-WRT given you know the MAC address of the VM. Easy peasy.
- Disable time synchronization:
- in HyperV VM settings, under Management, Integration Services, disable the Time Synchronization option
- in Windows Services of the VM, disable and stop the Windows Time service
- in the registry of the VM, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Parameters and set Type to NoSync (most likely was Nt5DS before)
- Shutdown the VM and take a snapshot (checkpoint in HyperV terminology)
If/when the trial stops, just restore the snapshot. Of course this is a last resort option, I hope I won't have to do that. Plus, all changes made in between would be lost.
Source 1 Source 2 Source 3, slightly related only as it is for DC