I hope this is the right forum to pose this question! We're trying to figure out why our primary domain controller keeps bumping the time ahead by approximately six minutes whenever we attempt to synchronize time with another server. Over the course of our investigation, we've seen that after restarting the w32tm service and telling the service to synchronize with one specific server (in our case, 0.pool.ntp.org), we see the system jump to the correct time and then, approximately five seconds later, jump back to ~344.25 seconds ahead! (According to the stripchart, anyway.) We're certain we can rule out a problem with the server to which we're syncing, because it appears to work very, very briefly--does anyone have any idea what could be re-offsetting the server clock that much? All help greatly appreciated. Thank you for reading!

Show results of all "w32tm /query /..." commands

[Configuration] EventLogFlags: 2 (Local) AnnounceFlags: 5 (Local) TimeJumpAuditOffset: 28800 (Local) MinPollInterval: 6 (Local) MaxPollInterval: 10 (Local) MaxNegPhaseCorrection: 172800 (Local) MaxPosPhaseCorrection: 172800 (Local) MaxAllowedPhaseOffset: 300 (Local) FrequencyCorrectRate: 4 (Local) PollAdjustFactor: 5 (Local) LargePhaseOffset: 50000000 (Local) SpikeWatchPeriod: 900 (Local) LocalClockDispersion: 10 (Local) HoldPeriod: 0 (Local) PhaseCorrectRate: 7 (Local) UpdateInterval: 100 (Local) [TimeProviders] NtpClient (Local) DllName: C:\Windows\system32\w32time.DLL (Local) Enabled: 1 (Local) InputProvider: 1 (Local) AllowNonstandardModeCombinations: 1 (Local) ResolvePeerBackoffMinutes: 15 (Local) ResolvePeerBackoffMaxTimes: 7 (Local) CompatibilityFlags: 2147483648 (Local) EventLogFlags: 1 (Local) LargeSampleSkew: 3 (Local) SpecialPollInterval: 3600 (Local) Type: NTP (Local) NtpServer: clock.tix.ch,0x1 (Local) NtpServer (Local) DllName: C:\Windows\system32\w32time.DLL (Local) Enabled: 1 (Local) InputProvider: 0 (Local) AllowNonstandardModeCombinations: 1 (Local) VMICTimeProvider (Local) DllName: C:\Windows\System32\vmictimeprovider.dll (Local) Enabled: 1 (Local) InputProvider: 1 (Local) One of my co-workers apparently changed the source to clock.tix.ch (which is currently reporting an average of 343.24s offset) while I wasn't looking.

Also: Peer: clock.tix.ch,0x1 State: Active Time Remaining: 1457.9430000s Mode: 1 (Symmetric Active) Stratum: 0 (unspecified) PeerPoll Interval: 6 (64s) HostPoll Interval: 6 (64s) Leap Indicator: 0(no warning) Stratum: 3 (secondary reference - syncd by (S)NTP) Precision: -6 (15.625ms per tick) Root Delay: 0.0000000s Root Dispersion: 10.0000000s ReferenceId: 0xB2D132F7 (source IP: 178.209.50.247) Last Successful Sync Time: 2/17/2012 2:13:09 PM Source: clock.tix.ch,0x1 Poll Interval: 6 (64s)

Run "w32tm /monitor". You'll get result like this SomeDC.domain.net [x.x.x.x]: ICMP: 61ms delay. NTP: -0.0323784s offset from Your PDC emulator RefID: real.ntp.server [x.x.x.x] if "real.ntp.server" if one of your DCs run commands 1. w32tm /config /syncfromflags:domhier /reliable:no /update on "real.ntp.server" 2. w32tm /config /syncfromflags:domhier /reliable:yes /update on PDC emulator

Okay, now we're not sure exactly what's happening. It doesn't matter if we've removed all the settings from Windows Time and stopped the service; whenever we change the time on the PDC (which is also in charge of synchronizing everything else), even manually, to whatever...it jumps back to T+344s.

All right, figured it out, and it's because of something I didn't declare ahead of time here: our primary DC is a VM, and it's pulling the time from the HV. We'll configure the HV to manage the synchronization.

Enabling a HV Time Syncronization with DC is very bad idea, because your forest time syncronization will be broken. Optimal scenario is 1) Disable VM timesync with Host. 2) Configure timesync: Internet Time Source <-> PDC <-> DCs <-> Member Servers/Clients 3) Make sure timesync is working. read this tread http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/d359e5d4-1da6-4b81-9fd2-1acca4ca5311

Hello, please see the following article how to configure time synv with Hyper-V: http://blogs.msdn.com/b/virtual_pc_guy/archive/2010/11/19/time-synchronization-in-hyper-v.aspx http://technet.microsoft.com/en-us/library/cc773061(WS.10).aspxBest regards Meinolf Weber MVP, MCP, MCTS Microsoft MVP - Directory Services My Blog: http://msmvps.com/blogs/mweber/ Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.