Before you configure a manual time source for a client computer, you can determine the time difference between it and the source as a means to test basic NTP communication. After completing the configuration on the selected client computer, be sure to monitor the System log in Event Viewer for W32Time errors.

Note
For more information about the w32tm command, type w32tm /? at a command prompt or see Windows Time Service Tools and Settings on the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=42984).

Administrative Credentials

To perform this procedure, you must be a member of the Administrators group on the local computer. To perform this procedure from a remote computer, you must be a member of the Domain Admins group.

1. Open a Command Prompt.

2. Type the following command to display the time difference between the local computer and a target computer, and then press ENTER:

   w32tm /stripchart /computer: target /samples: n /dataonly

    

   Value	Definition
   target	Specifies the DNS name or IP address of the NTP server that you comparing the local computer's time against.
   n	Specifies the number of time samples that will be returned from the target computer to test basic NTP communication.

3. Open UDP port 123 for outgoing traffic on firewall if needed.

4. Open UDP port 123 (or a different port you have selected) for incoming NTP traffic.

5. Type the following command to configure a manual time source for the selected computer and then press ENTER:

   w32tm /config /manualpeerlist: peers /syncfromflags:manual /update

   where peers specifies the list of DNS names or IP addresses of the NTP time source(s) that the selected computer will synchronize from. When specifying multiple peers, use a space as the delimiter and enclose them in quotation marks.