Incorrect time source on DCs Server 2008 domain?

Solution 1:

It does look like things are out of whack regarding the time source some of the non-PDC emulator DC's are using. I would suggest running the following on all DC's, with the exception of the PDC emulator:

w32tm /config /syncfromflags:domhier /update. Then restart w32time.

As far as syncing the PDC emulator to an external source, such as the firewall, my question would be is it neccessary? Time is relative. It's perfectly acceptable to have a "closed system", unless you need true, accurate time from an external source for auding, legal, etc. reasons. If you do, then you probably need to sync to something other than the firewall.

Solution 2:

Part of the problem with a DC in virtual is it wants to get it's time from PDC, but the "virtual drivers" are set by default to sync time with host. This will cause a tug-of-war if the host and PDC are not the same time. Most people will just disable the VM time-sync feature but this would cause an issue if the VM is ever saved vs. shutdown.

In Hyper-V world for the PDC: The following steps set the VM to use Host on boot, sleep/awake, and snapshot recovery but once OS is up, it will use the manualpeerlist for time sync. You should also have the host syncing time with the same sources so your host/guests are only 5-10 seconds apart max.

Open an Admin prompt and type the following commands:

reg add HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\VMICTimeProvider /v Enabled /t reg_dword /d 0

(answer yes to overwrite and disable this time source)

w32tm /config /syncfromflags:MANUAL /reliable:YES /manualpeerlist:"us.pool.ntp.org,0x1" /update

net stop w32time & net start w32time

w32tm /resync /force

(should complete successfully)

w32tm /query /source

(should show NTP server IP/name)

I pulled this together from TechEd and a great virtualization post at Microsoft after helping several clients overcome time issues with DC's/PDC being in virtual. http://blogs.msdn.com/b/virtual_pc_guy/archive/2010/11/19/time-synchronization-in-hyper-v.aspx