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We've just had a daylight saving change over here in NZ and some of my servers haven't changed over.

I've syncronised the PDC with an NTP server which is working. The PDC has the correct time. Other machines in the domain do not. I tried changing the other machines manually but after a few minutes the time jumped back 1 hour. How do I fix this? I read somewhere that the other machines in the domain sync to the PDC. Clearly that's not happening quite right.

Windows Server 2003 doesn't seem to log anything about when the time on the server has changed.

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up vote 0 down vote accepted

Has there been a Windows Update for daylight saving that wasn't applied to all the servers?

There's this update for Windows Server 2003 (for example) that states:

Installing this update enables your computer to automatically adjust the computer clock on the correct date in 2007 due to revised Daylight Saving Time laws in many countries.

but unfortunately doesn't state which countries are affected. It could well be that there have been subsequent updates for 2008 and 2009, which I didn't find.

Check that there aren't any updated pending for the affected machines.

Check Windows Update from the affected machines to see if anything's missing.

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Installed that patch just to make sure. It made no difference. Running windows update to see if that helps. I'm not that hopeful. – Matt Sep 27 '09 at 21:33
Ok, there are updates that need installing but i can't do that just yet. I've manually updated the rules with tzedit. Takes a while but eventually it updates correctly. – Matt Sep 27 '09 at 22:09

The NTP server only provides the time in UTC, which is what Windows uses internally. The conversion from UTC to a local timezone for display is handled individually by each server's software. Your servers probably all agreee on what time it is (i.e. they have the same UTC time), but they are disagreeing on whether daylight savings is in effect (that is, they are probably reporting local times differing by exactly one hour).

Daylight savings rules are subject to the whims of politicians (and many juristrictions followed the U.S. in meddling with their rules in 2007). Windows incorporates the rules known for each juristiction when it was released, but requires updates to find out what the politicians have been up to since it was released.

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Thanks for the explanation. – Matt Sep 27 '09 at 22:10

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