Time server

[MS2011]

Morning,

 

NTP server not functioning properly. My predecessor installed the role on secondary dc.

 

I have moved the role onto PDC emulator. My primary DC synchronise time with external time source and all the clients/member server attempt to sync with dc.

 

On PDC - I can’t turn off adjust for daylight saving time automatically. If I turn off, time changes (1hr behind).

 

PDC should get sync and time for external source?

 

Any advice???

 

Thanks

MS

[Davit2005]

PDC emulator is a role held by a DC and deals with time, windows workstations and servers in the domain should look at this by default for time and yes the server holding the PDC role should be configured to get time from an external time source such as 0.uk.pool.ntp.org .

 

https://learn.microsoft.com/en-us/windows-server/networking/windows-time-service/windows-time-service-top

 

Windows Time service technical reference. The W32Time service provides network clock synchronization for computers without the need for extensive configuration. The W32Time service is essential to the successful operation of Kerberos V5 authentication and, therefore, to AD DS-based authentication.

 

How the Windows Time service works. Although the Windows Time service is not an exact implementation of the Network Time Protocol (NTP), it uses the complex suite of algorithms that is defined in the NTP specifications to ensure that clocks on computers throughout a network are as accurate as possible.

 

Windows Time service tools and settings. Most domain member computers have a time client type of NT5DS, which means that they synchronize time from the domain hierarchy. The only typical exception to this is the domain controller that functions as the primary domain controller (PDC) emulator operations master of the forest root domain, which is usually configured to synchronize time with an external time source.

Edited April 18, 2023 by Davit2005

[MS2011]

PDC emulator is a role held by a DC and deals with time, windows workstations and servers in the domain should look at this by default for time and yes the server holding the PDC role should be configured to get time from an external time source such as 0.uk.pool.ntp.org .

 

Which I did but as soon as turn off day light saving time, it goes 1hr behind.

[FragglePete]

Something thats caught me out in the past, if using Hyper-V ensure the Time Synchronization services are turned off for the VM. This sort of forces the VM to use the host on board clock, and if this is out then you'll get issues. I had this several years ago when the clocks changed with clients winding their clocks back.

 

Switched this off, set the PDC Emulator to get an external time source, the other DCs then look at the PDC for clock syncs and then all your clients sync themselves from any of the DCs at boot time, etc.

 

Pete

[Davit2005]

Something thats caught me out in the past, if using Hyper-V ensure the Time Synchronization services are turned off for the VM. This sort of forces the VM to use the host on board clock, and if this is out then you'll get issues. I had this several years ago when the clocks changed with clients winding their clocks back.

 

Switched this off, set the PDC Emulator to get an external time source, the other DCs then look at the PDC for clock syncs and then all your clients sync themselves from any of the DCs at boot time, etc.

 

Pete

 

Yes that is a good point. Might be worth setting the NTP server on the hypervisor to a reliable source too if possible :-)

Edited April 18, 2023 by Davit2005

[Oaktech]

I configured this about 10 years ago and haven't touched it since!

 

https://theitbros.com/configure-ntp-time-sync-group-policy/

[JRA]

Did once have an utterly infuriating faff with this. Whatever I did, whatever guide I followed or how beautifully simple the rest of the world found it or however many times this had worked before on everyone else's networks I could NOT get it to behave.

 

In the end I set the Smoothwall box the place had as NTP server and that worked fine.

[msi_school]

PDC emulator is a role held by a DC and deals with time, windows workstations and servers in the domain should look at this by default for time and yes the server holding the PDC role should be configured to get time from an external time source such as 0.uk.pool.ntp.org .

 

Which I did but as soon as turn off day light saving time, it goes 1hr behind.

 

We are in British summer time so GMT is an hour behind.

[MS2011]

See attached, right now time correct. As soon as I turn of this option, 1hr behind.

 

My understanding is NTP sever get time from external source so this option should be turned off.

[MS2011]

NTP server configuration

[Koldov]

Ours is on.

 

I thought as much but see below for confirmation (first internet search came up with this):

 

"Because NTP is based on UTC which does not have a daylight savings time period, a switchover is not necessary inside the NTP system. The operation systems of servers and clients are solely responsible for switching from/to DST."

 

https://www.meinbergglobal.com/english/faq/faq_33.htm#:~:text=Because%20NTP%20is%20based%20on,for%20switching%20from%2Fto%20DST.

 

EDIT: Link is provided purely as credit, not an invitation/advertisement/recommendation to visit...

Edited April 20, 2023 by Koldov

[MS2011]

So my settings are correct?

[MS2011]

What’s the difference between;

 

0.uk.pool.NTP.org,0x1

 

And

 

0.uk.pool.NTP.org

[Koldov]

So my settings are correct?

 

Yes.

 

NTP (advertises UTC) > DC (converts to DST) > CLIENT

 

Although it might be a little more complicated than that... for instance all my clients have 'Adjust for daylight saving time automatically' set, but these don't take/add the extra hour from the time the DC is advertising... something clever to do with the fact that the server knows it is getting UTC (Type: NTP (Local)) time and the clients know it is getting DST (Type: NT5DS (Local)) - basically whatever the DC tells it the time is (which might negate the other settings on the client I've never tested it)...

Edited April 20, 2023 by Koldov

[Koldov]

What’s the difference between;

 

0.uk.pool.NTP.org,0x1

 

And

 

0.uk.pool.NTP.org

 

I think these are to do with 'poll intervals' (or how often it requests an update) but there are other flags that deal with how it treats each server you've specified - as a main, fallback, etc.

 

"Each time source may also be followed by a comma and a DWORD containing flags for special handling of that time source"

 

https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc779560(v=ws.10)?redirectedfrom=MSDN

 

EDIT: Link is provided purely as credit, not an invitation/advertisement/recommendation to visit...

Edited April 20, 2023 by Koldov