Configuring external time source on your Primary Domain Controller

1. Find out what your primary domain controller (PDC) is for your domain by executing the following powershell commands from any machine in the domain
   1. [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest().RootDomain.PdcRoleOwner.Name
      
2. Login to your primary domain controller
3. Open up a command prompt/powershell window with administrative privileges
4. Execute the following command to configure the domain controller to look at an external time source
   1. w32tm.exe /config /manualpeerlist:”0.us.pool.ntp.org 1.us.pool.ntp.org 2.us.pool.ntp.org 3.us.pool.ntp.org” /syncfromflags:manual /reliable:YES /update
      
      1. Notes: You can find the closest time server near you by browsing the following page and clicking on the nearest zone: http://www.pool.ntp.org/zone/@
5. Execute the following command to actually perform a time synchronization with the external source
   1. w32tm.exe /config /update
      
6. Execute the following command for the changes to take effect
1. Restart-Service w32time
   

Source: jackstromberg