[ntp:questions] Issues with w32tm on AD network

Martin Burnicki martin.burnicki at meinberg.de
Tue Feb 26 10:53:50 UTC 2008

Jason Rabel wrote:
> I *believe* you can also tell the PDC (via some w32time command) that the
> primary time source is another machine, and all clients will use that. Of
> course that means another machine to manage rather than just installing
> ntpd on it.
> If you search the MS website for words like "NTP Domain Controller"
> there's a lot of info that pops up.

I've already read a bunch of KB articles about Windows time synchronization.
Unfortunately most of those articles care about special problems with
w32time, while other articles are pretty common only and don't cover
specific scenarios.

A common configuration for our customers which install a PCI card as a
primary time source would be as follows:

- Install the PCI card in the root PDC

- Since w32time does not support the PCI card directly, install our driver
which is shipped with the card and let the PDC's system time be
synchronized by our driver.

- Run w32time (or ntpd) configured not to touch the system time but make the
diciplined time available on the network

This is pretty easy using ntpd with local clock at stratum 0, but we have
not been able to find a reliable way to configure w32time so that it
behaves as desired.

We have tried different registry settings, e.g. running

w32tm /config /reliable:yes

resulting in "AnnounceFlags" set to 5

Sometimes w32time has been working correctly for some time, but then
after a day suddenly stopped delivering time to it's clients.

So the best and most reliable configuration seemed to be to specify an
"external" NTP server on the PDC, which runs ntpd.

BTW, I've searched the MS pages again for the keywords you mention, and I
only receive search results when I start searching on www.microsoft.com. If
I start searching at support.microsoft.com the search returns no results,
which is pretty poor (for MS).

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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