Wednesday, June 1, 2011

Synchronize time with external NTP server on a Windows 2008 Server R2 DC

We have seen errors where users are not able to login to external SAAS applications on the Internet if the time sync is not correct. By default, the clients on a Windows network will get their time from a DC and DC gets its time from PDC. It is important that the PDC is syncronized from an external reliable source. Before you start this, make sure that if you have a firewall you open port 123 UDP both inbound and outbound.
1. Go to your PDC server, if you are not sure then open up a command prompt on a dc and type
c:\>netdom /query fsmo
You should see your PDC in the list
2. Login to the PDC and open up a command prompt and stop the W32time service
net stop w32time
3. Configure external time source, at the command prompt type:
C:\> w32tm /config /syncfromflags:manual /manualpeerlist:”,,”
4. Make the PDC a reliable time source for the clients on the network type:
c:\>w32tm /config /reliable:yes
5. Start the w32time service: c:\>net start w32time
6. The windows time service should now begin to synchronize the time, external NTP servers can be checked in the time configuration by typing:
c:\>w32tm /query /configuration
7. check the Event Viewer for any errors.

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