[ntp:questions] Issues with w32tm on AD network

Martin Burnicki martin.burnicki at meinberg.de
Mon Feb 25 14:42:34 UTC 2008


Andrew Hodgson wrote:
> On Fri, 22 Feb 2008 09:31:38 +0100, Martin Burnicki
> <martin.burnicki at meinberg.de> wrote:
>>Though it's normally preferable to run ntpd rather than w32time, there is
>>a limitation if you run ntpd on a domain controller:
>>The domain members (workstations) will stop detecting the domain
>>controller automatically as their primary time source, so you'll have to
>>configure the domain controller explicitely as times source on every
> Yes, I have found this in a previous life, plus it caused some other
> issues for us as well, which is why I would like to keep W32tm if
> possible.

Do you remember which kind of issues that were?

>>If you also run any Linux or other *ix server then a better approach would
>>be to let the *ix machine synchromize to the pool servers, and configure
>>the *ix machine as "internet time source" for w32time on the domain
> Unfortunately the Debian box I have is a laptop that is not on
> continuously, so no good.  I do have an ASA firewall and a Cisco
> router however, which at present are set to get time from the Windows
> box, but I could set one up as an NTP server perhaps?

I don't know the ASA firewall, but I've heard several times that routers
don't do a good job as NTP servers.

Maybe you have another Windows server on which you can install NTP. That
server could get the time from the pool servers, and the root PDC could run
w32time and get the time from the server running ntpd.

This is a good basic configuration if you want to use a built-in radio clock
or GPS receiver as time source, which come with their own driver software.

The reason is because it's hard to tell w32time that it does not need to
have an upstream time source configured and thus not touch the system time,
because the system time is already disciplined by another driver, and
w32time just had to distribute that synchronized time on the network.

With ntpd this configuration is pretty easy: just configure the local clock
as ref time source with stratum 0.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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