[ntp:questions] Synchronizing contrived time

Amit Dor-Shifer amit.dor.shifer at gmail.com
Tue Mar 11 20:30:07 UTC 2014


Hi William. The conf file appears in the post (I've cat-ed b4 executing
ntpd), and is exactly what I was suggested here initially.
Thanks,
Amit
On 12/03/2014 5:45 AM, "William Unruh" <unruh at invalid.ca> wrote:

> On 2014-03-11, Amit Dor-Shifer <amit.dor.shifer at gmail.com> wrote:
> > Hi.
> >
> > With the configuration I've been advised here, I'm still not able to
> > maintaine a skewed time on the server. ntpd does execute, yet a few
> seconds
> > after its initialization, it resets the time skew I've generated (I.E,
> even
> > b4 the client had a chance to query it)
>
> ??? It has nothing to "reset" with respect to. why do you not post your
> whole ntp.conf file here for the server?
>
>
> >
> > $ sudo tail -f /var/log/messages
> > #...snip
> > $
> > $
> > $ date
> > Tue Mar 11 20:43:03 EST 2014
> > $ cat ~/test_ntpd/ntp.conf
> > server 127.127.1.0 minpoll 4 maxpoll 4
> > $ sudo date -s "$(date) - 50 minute"
> > Tue Mar 11 19:53:30 EST 2014
> > $ date
> > Tue Mar 11 19:53:35 EST 2014
> > $ sudo ntpd -g -f ~/test_ntpd/ntp.conf
> > sudo: timestamp too far in the future: Mar 11 20:43:30 2014
> >
> > Mar 11 19:54:06  ntpd[31080]: ntpd 4.2.6p5 at 1.2349-o Sat Nov 23 18:21:48
> UTC
> > 2013 (1)
> > $ Mar 11 19:54:06  ntpd[31081]: proto: precision = 1.495 usec
> > Mar 11 19:54:06  ntpd[31081]: 0.0.0.0 c01d 0d kern kernel time sync
> enabled
> > Mar 11 19:54:06  ntpd[31081]: format error frequency file
> > /home/amit/test_ntpd/ntp.conf
> > Mar 11 19:54:06  ntpd[31081]: Listen and drop on 0 v4wildcard 0.0.0.0 UDP
> > 123
> > Mar 11 19:54:06  ntpd[31081]: Listen and drop on 1 v6wildcard :: UDP 123
> > Mar 11 19:54:06  ntpd[31081]: Listen normally on 2 lo 127.0.0.1 UDP 123
> > Mar 11 19:54:06  ntpd[31081]: Listen normally on 3 eth0 10.250.129.79 UDP
> > 123
> > Mar 11 19:54:06  ntpd[31081]: Listen normally on 4 lo ::1 UDP 123
> > #...snip
> > Mar 11 19:54:06  ntpd[31081]: peers refreshed
> > Mar 11 19:54:06  ntpd[31081]: Listening on routing socket on fd #22 for
> > interface updates
> >
> > $
> > $
> > $
> > $ date
> > Tue Mar 11 19:54:09 EST 2014
> > $
> > $
> > $
> > $
> > $ Mar 11 19:54:16  ntpd[31081]: 0.0.0.0 c016 06 restart
> > Mar 11 19:54:16  ntpd[31081]: 0.0.0.0 c012 02 freq_set kernel -25.992 PPM
> >
> > $
> > $ date
> > Tue Mar 11 19:54:21 EST 2014
> > $ Mar 11 20:44:23  ntpd[31081]: 0.0.0.0 c61c 0c clock_step +3000.023162 s
> > Mar 11 20:44:23  ntpd[31081]: 0.0.0.0 c614 04 freq_mode
> > Mar 11 20:44:24  ntpd[31081]: 0.0.0.0 c618 08 no_sys_peer
> >
> > $
> > $
> > $
> > $ date
> > Tue Mar 11 20:44:29 EST 2014
> >
> > David, when you were suggesting before that I didn't configure the
> correct
> > local clock driver - is that achieved via ntp.conf? Could you refer me to
> > an example?
> > Thanks
> >
> >
> > On Tue, Mar 11, 2014 at 6:12 AM, William Unruh <unruh at invalid.ca> wrote:
> >
> >> On 2014-03-10, Amit Dor-Shifer <amit.dor.shifer at gmail.com> wrote:
> >> > Thanks.
> >> > Would this then be the reference implementation?
> >> >
> >> > [user at centos test_ntpd]$ rpm -qf $(which ntpd)
> >> > ntp-4.2.6p5-1.el6.centos.x86_64
> >> > [user at centos test_ntpd]$ cat ~/test_ntpd/ntp.conf
> >> > server 127.127.1.0 minpoll 4 maxpoll 4
> >> > [user at centos test_ntpd]$ ps -ef|grep ntp
> >> > user     13411 12236  0 22:03 pts/0    00:00:00 grep ntp
> >> >
> >> > # moving clock back some 50 mins
> >>
> >> AAAAAARGH. No do not do that. ntpd is horrible at handlking sudden
> >> changes in time. It is like testing how good a car is by driving it off
> >> a cliff. It was never designed to fly.
> >>
> >>
> >> >
> >>
> >> _______________________________________________
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> >>
>
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