Windows Server Time Sync Configuration

The following steps can be used to configure DCs the default Windows time service hierarchy in an AD forest.  The procedure will also remove any errors in the Event Viewer, if any existed.

Do not use if you are using a third party stratum service and refer to the vendor’s documentation for further instructions

Check and Document the Current Time Configuration on the PDC Emulator

  1. First check and document the current configuration:
    1. All Windows Server domain operating systems – run the following on the forest root domain PDC Emulator.
      1. Note: In some cases you must wait a little time for the service to instantiate.
      2. If you do not see expected results immediately, wait 10 min and re-run the following steps
  2. W32tm /query /configuration   
    1. This command confirms the PDC Emulator shows the current source in the [TimeProviders] section, Look for “Type:” You will see one of the following:
      1. Type: NT5DS (Local)   -This means that it’s not synced externally.
      2. Type: NTP (Local)  –This command it is syncing externally.
                 NtpServer: time.windows.com [65.55.56.206] (Local)
    2. For all other DCs, use the command, w32tm /monitor (step 4 below)
  3. w32tm /query /source
    1. On the PDC Emulator, this shows the actual source. One of two possibilities:
      1. CMOS clock                    -Signifies not synced to an external source                                                  (Not what you want to see)
      2. time.windows.com  –The NTP source IPaddress/FQDN  This is correct.
  4. w32tm /monitor or w32tm /monitor /computers:DCNAME
    1. On the PDC Emulator, this command shows the outside time source.
      1. Good example:
        dc01.contoso.com *** PDC ***[10.10.10.200:123]:
        ICMP: 0ms delay
        NTP: +0.0000000s offset from dc02.contoso.com
        RefID: time.windows.com [65.55.56.206]
        Stratum: 4
    2. On all other DCs, this command shows the current time source DC for this DC.
      1. You will see an “offset for the PDC from its configured NTP source.
      2. Good example result showing the DC02 is syncing with dc01.contoso.com:
        dc02.contoso.com 10.10.10.210]:
        ICMP: 0ms delay
        NTP: +0.0000000s offset from dc01.contoso.com
        RefID: dc01.contoso.com [10.10.10.200]
        Stratum: 4
  5. w32tm /tz
    1. This shows the current time zone to make sure it’s correct.
  6. w32tm /stripchart /computer: target /samples: n /dataonly
    1. This command will show you the time difference between the local computer and a target computer and is helpful in determining if there is an offset. The “n” value is the number of time samples that will be returned from the target to test basic NTP communications.
  7. w32tm /dumpreg
    1. This command dumps the current registry settings found in:
      HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters
      You can see the current time service configuration entries, such as:
      Type:  NTP
      NTPServer:

Configure time sync to a reliable source on the forest rood domain PDC Emulator ONLY.

Do not perform on any other DC in any domain in the forest. PDC in the forest root only.

  1. Windows 2003 and all newer:
    1. Open an Administrator Command Prompt.
      1. Note that the examples below use either time.windows.com or the pool.ntp.org servers. You can get a full list of reliable time services at:
        A list of the Simple Network Time Protocol (SNTP) time servers that are available on the Internet: http://support.microsoft.com/kb/262680
    2. w32tm /config /manualpeerlist:time.windows.com /syncfromflags:manual /reliable:yes /update
      OR – if you want to use the pool.ntp.org time source servers:
    3. W32tm /config /manualpeerlist:0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,0x1 /syncfromflags:manual /reliable:yes /update
    4. w32tm /resync /rediscover
    5. net stop w32time && net start w32time
    6. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below.
  2. Windows 2000:
    Generally speaking, the w32tm command is similar to Windows 2003 and newer operating systems.  However, Windows 2000 uses the net time /setsntp method, which was removed in later versions.  There are also some differences between Windows 2000 RTM and various service packs. Therefore, if any issues arise from the commands not setting, it’s recommended to follow the instructions using the registry to configure the time service in Windows 2000:
    How to configure an authoritative time server in Windows 2000:
    http://support.microsoft.com/kb/216734

    1. Open an Administrator Command Prompt.
    2. net time /setsntp:174.140.19.7    – Windows 2000 uses this command to configure an outside source.
    3. net stop w32time
    4. w32tm -once      W32tm performs numerous commands. Their results are displayed on the screen.
    5. net start w32time
    6. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below
  3. Use the procedure in Step #1 to check and document the new configuration.
  4. Contingency: Perform the steps in the Corrupted Time Service Resolution Section to return the settings back to Windows defaults.

Configure all other DCs to sync using the forest time hierarchy

This includes all other DCs in the forest root domain that are not holding the PDC Emulator role, and any DC in any other domains and trees, including the PDC in those domains.

Do NOT run the following on the PDC Emulator in the forest root domain.

  1. First check and document the current configuration: See Section #3 above.
  2. Windows Server 2003 and all newer server operating systems:
    1. Open an Administrator Command Prompt
    2. w32tm /config /syncfromflags:domhier /update /reliable:no
    3. w32tm /resync /rediscover
    4. net stop w32time && net start w32time
    5. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below
  3. Windows 2000:
    For reference with Windows 2000, see the following link for more info:
    How to configure an authoritative time server in Windows 2000
    http://support.microsoft.com/kb/216734

    1. Open an Administrator Command Prompt.
    2. w32tm –s
    3. Net stop w32time && net start w32time
    4. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below
  4. Use the procedure in Step #1 to check and DOCUMENT the new configuration.
  5. Contingency: Perform the steps in the Corrupted Time Service Resolution Section to return the settings back to Windows defaults.

Time configuration on FSMO transferred or seized DCs

  1. On the new forest root domain PDC Emulator, run the following:
    1. Open an Administrator command prompt:
    2. W32tm /config /manualpeerlist:0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org /syncfromflags:manual /reliable:yes /update
      1. Note: time.windows.com is a working time source, however you choose any reliable time services in your locale.
    3. W32tm /resync /rediscover
    4. net stop w32time && net start w32time
    5. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below
  2. On the server formerly holding the PDC Emulator role, run the following:
    1. Open an Administrator command prompt.
    2. w32tm /config /syncfromflags:domhier /update
    3. w32tm /resync /rediscover
    4. net stop w32time && net start w32time
    5. Check it with W32tm /query /configuration   
      1. You may have to repeatedly run it a few times until you see it change from the CMOS clock to the time server you set it to. If it doesn’t change after a few minutes, you may have to reset the time service in the Contingency section below
  3. Follow the procedure in Step #1 to check and DOCUMENT the new configuration.
  4. Contingency: Perform the steps in the Corrupted Time Service Resolution Section to return the settings back to Windows defaults.

Corrupted Time Service Resolution Section (Contingency)

If any of the procedures did not work or event log errors indicate any issues, you can reset the time service registry entries back to default. The procedure should be done on the DC that you are experiencing issues with and not necessarily on each DC.  Note: This procedure can also be used as a contingency to return a DC (PDC and non-PDCs) back to local CMOS time sync.

  1. On the DC that you’re experiencing issues with, run the following:
    1. Open an Administrator command prompt.
    2. net stop w32time
    3. w32tm /unregister
    4. w32tm /register
    5. net start w32time
    6. Configure the DC according to the configuration sections above depending on if it’s a PDC Emulator or non-PDC Emulator.
  2. The next command is ONLY for Windows 2000 to 2008 DCs. It does not apply to 2008 R2 or newer and will be ignored if you try it.
    1. “net time /setsntp: ”      – Do not use the quotes. Note that there’s a blank space prior to the closing quote.
      This command tells the client (whether a DC or workstation) to delete the current registry settings for time and use default settings.
    2. net stop w32time && net start w32time
    3. Configure the DC according to the configuration sections above depending on if it’s a PDC Emulator or non-PDC Emulator.

W32Time Service Accuracy

Please bear in mind that the Windows W32Time service is not a full featured, accurate service for time sensitive application requirements, nor will Microsoft support it as such. You must use a third party time service that will support this requirement.

For more information, please visit the following link:

Support boundary to configure the Windows Time service for high-accuracy environments
http://support.microsoft.com/kb/939322

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References

How the Windows Time Service Works
http://technet.microsoft.com/en-us/library/71e76587-28f4-4272-a3d7-7f44ca50c018

Windows Time Service Technical Reference
http://technet.microsoft.com/en-us/library/a0fcd250-e5f7-41b3-b0e8-240f8236e210

Windows Time Service Tools and Settings
Includes specific w32tm command switches and registry entries.
http://technet.microsoft.com/en-us/library/cc773263

 

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