Event ID 12 — Domain Hierarchy Time Source Acquisition

Updated: November 25, 2009

Applies To: Windows Server 2008

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An Active Directory forest has a predetermined time synchronization hierarchy. The Windows Time service (W32time) synchronizes time between computers within the hierarchy, with the most accurate reference clocks at the top. If more than one time source is configured on a computer, the Windows Time service uses Network Time Protocol (NTP) algorithms to select the best time source from the configured sources, based on the computer’s ability to synchronize with that time source. Currently, the Windows Time service is synchronizing time with a time source peer from the domain heirarchy.

Event Details

Product: Windows Operating System
ID: 12
Source: Microsoft-Windows-Time-Service
Version: 6.0
Symbolic Name: MSG_DOMAIN_HIERARCHY_ROOT
Message: Time Provider NtpClient: This machine is configured to use the domain hierarchy to determine its time source, but it is the PDC emulator for the domain at the root of the forest. There is no machine above this machine in the domain hierarchy to use as a time source. It is recommended that you either configure a reliable time service in the root domain, or manually configure this PDC emulator in the root domain to synchronize with an external time source. Otherwise, this machine will function as the authoritative time source in the domain hierarchy. If an external time source is not configured or used for this computer, you may choose to disable the NtpClient.

Resolve

Configure an external time source

This computer is configured to hold the primary domain controller (PDC) emulator operations master role (also known as flexible single master operations or FSMO) in the forest root domain. This computer should not use itself as a time source. Configure an external time source as the authoritative time source for the forest, or configure a member domain controller as the time source peer. The configuration must be done manually. Perform the following procedure on the computer that is logging the event to be resolved.

To perform this procedure, you must have membership in Domain Admins, or you must have been delegated the appropriate authority.

To configure a manual time source peer:

  1. Open a command prompt as an administrator. To open a command prompt as an administrator, click Start. In Start Search, type Command Prompt. At the top of the Start menu, right-click Command Prompt, and then click Run as administrator. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
  2. At the command prompt, type w32tm /config /manualpeerlist:server,0x8, /syncfromflags:manual /update, where server is the name of the time source that you want to configure, and then press ENTER.
  3. Restart the Windows Time service. At the command prompt, type net stop w32time & net start w32time, and then press ENTER.
  4. Resynchronize the Windows Time service client with the time source peer. At the command prompt, type w32tm /resync, and then press ENTER.

To learn more about the Windows Time service and related tools, see Windows Time Service Tools and Settings (http://go.microsoft.com/fwlink/?LinkID=42984).

Verify

To perform this procedure, you must have membership in Administrators, or you must have been delegated the appropriate authority.

To verify that the Windows Time service is synchronizing correctly:

  1. Open a command prompt as an administrator. To open a command prompt as an administrator, click Start. In Start Search, type Command Prompt. At the top of the Start menu, right-click Command Prompt, and then click Run as administrator. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
  2. At the command prompt, type W32TM /resync, and then press ENTER.
  3. At the command prompt, type W32TM /query /status, and then press ENTER.

    This command displays the status of the Windows Time service synchronization. The Last Successful Sync Time line of the output displays the date and time that you ran the W32TM /resync command in the previous step. Also, check the computer name that is shown as the Source. This should be the name of a domain controller (or an administrator-configured time server) in the same Active Directory domain as the local computer.

To verify that the Windows Time service synchronized successfully with its time source, confirm that Event IDs 35 and 37 appear in Event Viewer. If there was a recovery from a previous failure to synchronize with the time source, you also see Event ID 138, which indicates that the Windows Time service is synchronized correctly.

For more information about the Windows Time service, see the Windows Time Service Technical Reference (http://go.microsoft.com/fwlink/?LinkID=25393).

Related Management Information

Domain Hierarchy Time Source Acquisition

Active Directory

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