Synchronize Windows Server Clock with Internet Time Server

Windows includes the Windows Time service - W32Time. The purpose of W32Time is to make sure that all computers that are running Microsoft Windows 2000 or later versions in an organization use a common time.

Time Hierarchy

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 as client desktop computers.
• Domain controllers may nominate the primary domain controller (PDC) operations master as their in-bound time partner but may use a parent domain controller based on stratum numbering.
• All PDC operations masters follow the hierarchy of domains in the selection of their in-bound time partner.
• It is therefore a good idea to synchronize your DC's with a Internet Time Server to ensure that your clock is up to date.

Synching to an External Time Source

Edit the following registry entries:

HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\Type

Change the value from NT5DS to NTP. This sets the server to sync from an NTP server on the internet.

HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config\AnnounceFlags

Change the value from 10 to 5. This marks the server as a reliable time server. In a correctly configured domain, client computers will update their system time from the domain controller.

HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters\NtpServer

This registry entry specifies a space-delimited list of stratum 1 time servers from which the local computer can obtain reliable time stamps. The list may consist of one or more DNS names or IP addresses (if DNS names are used then you must append ,0x1 to the end of each DNS name). For example, to synchronize the PDC Emulator in your forest root domain with tock.usno.navy.mil, an open-access SNTP time server run by the United States Naval Observatory, change the value of the NtpServer registry entry from time.windows.com,0x1 to time.nist.gov,0x1 here. Alternatively, you can specify the IP address of this time server, which is 192.43.244.18.

Now you can either reboot the server or stop and start the time service by running the following two commands:

net stop w32time
net start w32time

More details and options can be found at:

• Configuring the Windows Time Service
• How to configure an authoritative time server in Windows Server