How to Configure Atomic Time in Windows Server 2008

Last Review: August 7, 2010
Product(s): Windows Server 2008, Windows Server 2008 R2

By default, Windows-based computers use the following hierarchy:

• All client desktop computers nominate the authenticating domain controller as their in-bound time partner.

• All member servers follow the same process that client desktop computers follow.

•  All domain controllers in a domain nominate the primary domain controller (PDC) operations master as their in-bound time partner.

To configure atomic time, make the following registry settings on the domain controller running the PDC role. Note that if the domain controller is a virtual guest sever, you perform these settings on the Hyper-V host. In addition, SNTP UDP port 123 must be open on the firewall.

1. Open the Registry. Click Start, click Run, type regedit, and then click OK. Locate the following registry subkeys and modify the values as shown.

2. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\Type
   Type: NTP

3. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\AnnounceFlags
   AnnounceFlags: 5 DWORD

4. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer
   Enabled: 1 DWORD

5. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters
   NtpServer: 139.78.135.14,0x1
   (Oklahoma State University Central Time Zone)

6. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\
   NtpClient\SpecialPollInterval
   SpecialPollInterval: 900 Decimal

7. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\MaxPosPhaseCorrection
   MaxPosPhaseCorrection: 3600 Decimal

8. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\MaxNegPhaseCorrection
   MaxNegPhaseCorrection: 3600 Decimal

9. Quit Registry Editor.

10. At the command prompt, type the following command to restart the Windows Time service, and then press ENTER:
    net stop w32time && net start w32time