Time Synchronization in an Active Directory Environment

In an Active Directory environment the default time source is the domain controller in your forest root domain that is running the PDC emulator FSMO role. Keep in mind that the PDC emulator FSMO role is a domain level FSMO role so each domain will have one, but each domain’s PDC emulator will receive its time from the forest root’s PDC emulator. The following procedure will walk you through the steps of configuring the forest root’s PDC emulator to receive its time updates from an Internet time server.

If you don’t know which one of your Active Directory domains is the forest root domain, there are several articles on the Internet to easily determine which one is the forest root. Here’s one of those articles at Windows IT Pro.

From a domain controller in the forest root domain, determine the PDC emulator by running netdom /query fsmo


On the PDC emulator, configure the following registry value to “5”: HKLM>System>CurrentControlSet>Services>W32Time>Config>AnnounceFlags


Configure the following registry value to “1800” decimal (30 minutes): HKLM>System>CurrentControlSet>Services>W32Time>Config>MaxNegPhaseCorrection


Configure the following registry value to “1800” decimal (30 minutes): HKLM>System>CurrentControlSet>Services>W32Time>Config>MaxPosPhaseCorrection


Configure the following registry value to “tock.usno.navy.mil,0x1”: HKLM>System>CurrentControlSet>Services>W32Time>Parameters>NtpServer


Configure the following registry value to “NTP”: HKLM>System>CurrentControlSet>Services>W32Time>Parameters>Type


Configure the following registry value to “900” decimal (15 minutes): HKLM>System> CurrentControlSet>Services>W32Time>TimeProviders>NtpClient>SpecialPollInterval


Verify the following registry value is set to “1”: HKLM>System>CurrentControlSet> Services>W32Time>TimeProviders>NtpServer>Enabled


Restart the Windows Time (w32time) service.


If any of the PDC emulators are running as a virtualization guest on a Hyper-V server, see my Active Directory Time Synchronization Problems with Hyper-V blog.