[ntp:questions] ntpdate synchronization often fails

Yoann Fages yoannft at googlemail.com
Fri Nov 7 09:08:42 UTC 2008


Thanks Steve for your answer

I have changed my conf file with your advices.

Indeed, ntpd takes less time to synchronize at the beginning with the
"minipoll" instruction.

But I still have failed synchronizations.

So, I am going to try the last snapshot dev.


Thanks a lot.

Yoann.

2008/11/6 Steve Kostecke <kostecke at ntp.org>

> On 2008-11-06, Yoann Fages <yoannft at googlemail.com> wrote:
>
> > I am trying to set up a ntp server on an embedded linux platform. My
> > platform will be connected to a switch (not connected to internet) and
> all
> > clients will synchronize their clock with my platform local clock.
>
> The "synchronization" quality is directly related to the stability of
> the clock on your "platform".
>
> > I have downloaded and install ntpd, set up a conf file (ntp.conf) on my
> > platform:
>
> Assuming that you are using a stable release of NTP from www.ntp.org ...
>
> > conf file:
> >
> > server 127.127.1.0
>
> Ntpd will take a bit under 4 minutes to "synchronize" to the local clock
> if you use that server line.
>
> You may reduce this time to a bit under 60 seconds by appending 'minpoll
> 4' to that server line.
>
> > fudge 127.127.1.0 stratum 3 refid AmT3
>
> You should set the statum to something higher (i.e. 10, or more) just in
> case this private network is connected to a public network.
>
> > logfile /var/log/ntp.log
> > restrict default notrap nopeer nomodify
> > restrict 192.168.0.0 mask 255.255.0.0
>
> Those restrict lines are not affecting the issue you have raised. But
> why do you feel that they are neccessary?
>
> > On my platform I launch ntpd -c ntp.conf.
> >
> > On a linux PC connected to the switch, I launch: ntpdate -b -v
> server_ip_@
> >
> > Most of the time, I get this error message: "ntpdate : no server suitable
> > for synchronization found", but sometimes the synchronization is OK.
>
> You have to wait for ntpd on your "platform" to "synchronize" to the
> localclock.
>
> > What can I do to always have a synchronization?
>
> Speed up "synchronization" as shown above.
>
> Or use an NTP-dev snapshot; it accepts the Undisciplined Local Clock
> after the first poll.
>
> Or modify the source to suit your needs.
>
> Or consider other solutions such as timed, or rdate (on the clients)
> + inetd (on the "platform").
>
> --
> Steve Kostecke <kostecke at ntp.org>
> NTP Public Services Project - http://support.ntp.org/
>
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>



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