[ntp:questions] ntp-4.2.6p5 on Win 7 x64

Charles Swiger cswiger at mac.com
Tue Jul 22 17:04:10 UTC 2014


Hi--

On Jul 22, 2014, at 8:53 AM, Nick <me at privacy.net> wrote:
> The box is very lightly loaded.
> 
> ntp runs well on Mint 17 and the drift is reported to be -17ppm.

That seems to indicate that your hardware is sane and reasonable timekeeping
works fine under some platforms.

> ntp does not run well on Win 7 x64 and the drift is reported to be +493ppm.
> 

> What makes ntpd think that the frequency error on Windows is +493?

That implies that ntpd was unable to correct the drift and stabilize.
(+/- 500 ppm is the limit.)

> On reboot sometimes ntp starts with leap=11 and precision=-10.  Restarting 
> the service does not help.
> 
> Sometime ntp starts with leap=11 and precision=-22.  leap:=00 after maybe 
> 10 minutes.

Starting with leap=11 is normal; it's simply indicating that ntpd considers
itself to not be synchronized yet.  precision=-10 implies only MM timer
precision; a precision=-22 implies a much higher quality clock like ACPI or
HPET.

> Using the pool directive plus 3 server entries.  Reach rarely gets to 
> 377.  Often loses sync and resets.  Ping times to the servers are all 
> 30-35ms.

Can you setup a packet sniffer and see whether the UDP replies are getting
through but being dropped by the Windows box for some odd reason?

Try explicitly configuring the same four NTP servers under both Mint 17
and Windows, and compare what happens.

Regards,
-- 
-Chuck



More information about the questions mailing list