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Windows Time Synchronization

Before anything will work, you need to be sure that the computer functioning as the time server allows connections on port 123 both on the server itself and through any firewalls between the clients and the server.

• For Windows firewall settings reference, this is the path to allow connections to: %SystemRoot%\System32\w32tm.exe

BEFORE STARTING READ THIS

Don't change the clock by more than 10 minutes at a time! Doing so can cause AD or group policy or something super important to break!

The following is all to setup clients to sync with the server:

1. Run w32tm /query /source to see what the current time source is.
2. If it needs to be changed, run w32tm /config /manualpeerlist:*timeservers* /syncfromflags:manual /reliable:yes /update
   • to set more than one server, follow this example: w32tm /config /manualpeerlist:"timeserver1.domain or.activedirectory.server" /syncfromflags:manual /reliable:yes /update
   • you can also use internet time servers like w32tm /config /manualpeerlist:"0.pool.ntp.org, 1.pool.ntp.org, 2.pool.ntp.org" /syncfromflags:manual /reliable:yes /update
3. If the client is a VM, make sure that the time syncing service is off. This has to be set in the HyperV host settings for the VM.
4. Run net stop w32time && net start w32time to restart the time service
   • This may or may not be necessary, but it can jump start the process at the very least
5. The settings don't take hold immediately. In fact, running w32tm /query /source will most likely reutrn Local CMOS something or other. Give it a minute and try again, and it should say the correct source.
6. gg

Other useful commands and resources

• w32tm /query /peers
  • returns a list of "peers" to source time information from
• w32tm /monitor
  • prints the connection status to sources
• w32tm /query /configuration
  • prints the entire configuration
• reg query HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameter
  • checks the actual registry setting
• reference

this document last modified: January 30 2020 18:16

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