Setting NTP service for external Time source on PDC Emulator

Just a quick note to advise how I done this…in response to a call of course. Kerberos authentication is based on time stamps so time accuracy is vital in Microsoft Windows infrastructures.

Looked up this website technet ntp article
This looked the easiest as other sites wanted to edit the registry…I also backed up the regkey to the desktop on the domain controller I RDP'd to before editing the registry so I could put it back to the original settings.

To check how FSMO roles are configured on the domain

netdom query /domain:domain_name.co.uk fsmo

Schema owner             dc-1. domain_name.co.uk 
Domain role owner        dc-1 . domain_name.co.uk 
PDC role                 dc-2. domain_name.co.uk 
RID pool manager         dc-2 . domain_name.co.uk 
Infrastructure owner     dc-2. domain_name.co.uk 
The command completed successfully.

So now I know what is the PDC emulator, I know that  dc-2. domain_name.co.uk  is the server that will sync time to the domain.

From a CLI shell on dc-2. domain_name.co.uk 

w32tm /stripchart /computer:ip_addr_timesource /samples:5 /dataonly
Tracking ip_addr_timesource [ip_addr_timesource].

Collecting 5 samples.
The current time is 5/31/2010 1:52:31 PM (local time).
13:52:31, -00.1630267s
13:52:33, -00.1731537s
13:52:35, -00.1735452s
13:52:37, -00.1736697s
13:52:39, -00.1735333s

Note: there are time sources available on the internet, some organisations have one internal time source that syncs with an external time source then every internal network device syncs to that, you just have to choose what is best, that will depend on how network firewalls are configured on your network.

You can see time is out by 1/4 of a second, now type….

w32tm /config /manualpeerlist:ip_addr_timesource /syncfromflags:manual /reliable:yes /update

This syncs the PDC Emulator to your chosen time source ip_addr_timesource 

now we can test by typing 

w32tm /stripchart /computer: ip_addr_timesource  /samples:5 /dataonly

Tracking ip_addr_timesource [ip_addr_timesource]. 
Collecting 5 samples.
The current time is 5/31/2010 1:58:57 PM (local time).
13:58:57, +00.0060605s
13:58:59, -00.0001721s
13:59:01, -00.0005527s
13:59:03, -00.0002389s
13:59:05, -00.0002778s

Which is probobaly as close as you can get to being dead-on….depending on clock’s quartz crystals of the servers and lan devices!!!!!


Some links...

wiki/Time_server

pool.ntp.org/en/