[ntp:questions] NTP on Windows Server 2008 R2

Geir Guldstein geir.guldstein at gmail.com
Wed Feb 8 17:45:09 UTC 2012


I am currently working with NTP 4.2.6p5 on Windows Server 2008 R2 (64
bit). NTP works reasonably well before I install a certain device
driver, which of course must coexist with NTP in the final
configuration.

I observe the following on a fresh OS installation before the
mentioned device driver has been installed:
After ntpd has been running for a few hours ntpq reports offsets <
2ms.
When ntpd starts it reports the following to the OS event log:
ntpd 4.2.6p5 at 1.2349-o Jan 19 9:35:18 (UTC+01:00) 2012  (3)
Raised to realtime priority class
Performance counter frequency 3.021 MHz
Clock interrupt period 15.600 msec (startup slew -0.1 usec/period)
Windows clock precision 15.600 msec, min. slew 6.410 ppm/s
HZ 64.102 using 43 msec timer 23.256 Hz 64 deep
proto: precision = 0.300 usec
Listen and drop on 0 v4wildcard 0.0.0.0 UDP 123
Listen and drop on 1 v6wildcard :: UDP 123
Listen normally on 2 WAN fe80::795c:5b82:ec33:dd9 UDP 123
Listen normally on 3 WAN 192.168.1.52 UDP 123
Listen normally on 4 Loopback Pseudo-Interface 1 ::1 UDP 123
Listen normally on 5 Loopback Pseudo-Interface 1 127.0.0.1 UDP 123
peers refreshed

I stop NTP, delete the ntp.drift file, install the device driver,
restart the system and get the following:
Offsets reported by ntpq large are variable, they can be as large as
100-200ms and ntpd steps the clock. The system behaves this way even
when it has been running for several hours.
When ntpd starts it reports the following to the OS event log:
ntpd 4.2.6p5 at 1.2349-o Jan 19 9:35:18 (UTC+01:00) 2012  (3)
Raised to realtime priority class
Performance counter frequency 3.021 MHz
Clock interrupt period 15.600 msec (startup slew -0.2 usec/period)
Windows clock precision 0.500 msec, min. slew 6.410 ppm/s
using Windows clock directly
proto: precision = 500.000 usec
Listen and drop on 0 v4wildcard 0.0.0.0 UDP 123
Listen and drop on 1 v6wildcard :: UDP 123
Listen normally on 2 WAN fe80::795c:5b82:ec33:dd9 UDP 123
Listen normally on 3 WAN 192.168.1.52 UDP 123
Listen normally on 4 Loopback Pseudo-Interface 1 ::1 UDP 123
Listen normally on 5 Loopback Pseudo-Interface 1 127.0.0.1 UDP 123
peers refreshed

If I uninstall the device driver and restart the system NTP again
works reasonably well.

I will of course contact the device/driver vendor for support, but
wonder whether anyone here has advice to share.

Thanks,
Geir



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