[ntp:questions] Time of by 4 min

Martin Burnicki martin.burnicki at meinberg.de
Fri Mar 14 08:59:09 UTC 2014

David Taylor wrote:
> On 13/03/2014 17:48, greg.wayne.smith at gmail.com wrote:
>> That's a pretty slick program just from looking at the page. I will
>> play around with in and see. I tend to not install any 3rd party apps
>> on my DC's though.
>> I did mine the old fashion way by just setting the registry settings.
>> Basically this for Windows servers: http://www.pool.ntp.org/en/use.html
>> I have never had any issues till about 3 weeks ago.
>> My server is not slowing losing time... It's a solid 4 min off for the
>> past 3 weeks.
> Some versions of the Windows Time Service are broken - e.g. they get a
> time update once a week.  I strongly recommend using NTP from the
> Meinberg install set and updating to the latest development version,
> especially on your DCs.

As far as I know the default time update interval depends on the Windows 

For standalone machines the default w32time configuration is to poll 
time.windows.com once per week, but if the machine is installed as 
member of an Active Directory domain the default for clients and 
secondary servers is to figure out the authoritative time source for the 
domain via the directory, and poll this one more frequently.

Again, AFAIK, one of the domain controllers running w32time registers 
itself as authoritative time source for the domain, so the clients can 
automatically detect it. I'm not sure, however, how often this top-level 
w32time polls some upstream NTP source by default.

Ntpd is unable to register itself as authoritative time source for the 
domain, so if you replace w32time on the DC by ntpd then clients and 
secondary servers won't synchronize automatically anymore, so you had to 
configure each individual client and tell it where to get its time from.

So if you want to have an own NTP server for your network my advice is 
to set up an extra machine running ntpd e.g. with a GPS time source, and 
then just point the DC to this machine.

> [Caveats: I haven't used the Windows Time Service for many years, and I
> believe it is a little better now, and I don't run a domain.]

I'm not running a domain, either, but what I've written above is the 
conclusion from discussions here on the list and with our customers.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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