ntp synchronisation failed

[Corné Beerse]

T. Nifty Hat Mitchell wrote:

> On Thu, Jun 24, 2004 at 08:34:02PM +0200, Eric Tanguy wrote:
> 
> 
>>In the boot process the ntp synchronisation failed whereas after the
>>time synchronization is all right. Why ? may be because i use
>>firestarter ?
> 
> 
> If you have friends running Linux/Fedora exchange NTP privileges.
> 
> First look at how ntpd is started for you.
> 
> In general you will find that the initial connection using ntpdate
> times out for various normal reasons.  As a result the return status
> is an error.

You can chech for this behavoure to do a ping to the ntp-server. If you ping 3 
to 5 times, you will see the first ping takes longer than the others. Most 
likely, after this ping (before the ntpd-start) the first ntp query also succeeds.

Specially if you call the ntp-server by name, the IP-address is not cashed jet 
and hence a dns-query must be made. Since it is at boot time, most likely all 
routings and such also need to be setup.

If you have pinged the ntp-server (even only once!), all routers and name-caches 
are filled and the ntp-query can go strait on and will be substantial faster.

> 
> If you check back +15 min later things will be fine when ntpd has had time
> to make some connections.

However, if you start ntp only 15 minutes later, it is likely that the first 
call still is a little late.

> 
> Note that /etc/init.d/ntpd first starts ntpdate then ntpd.  It is not
> uncommon for ntpdate to fail in the early stages of booting a system
> for a list of reasons...

Not necessarily, newer ntpd-s have ntp-date build in and do that themself. If it 
is done separatly, this ntp-date will walk the paths for the next ntpd-s.

> 
> Do, find a ntp time service local to you.
> Based on the mail headers, perhaps  ntp.univ-nantes.fr 
> 
> or look here... http://www.eecis.udel.edu/~mills/ntp/clock2b.html

nice list.


> 
>     # FR ntp.obspm.fr
>     Location: BNM-SYRTE, Observatoire de Paris, Paris, France
>     Synchronization: NTP V4 secondary (stratum-2), i386/Linux
>     Service Area: France/Europe
>     Access Policy: open access, but please send a message to notify
>     Contact: info.bnm-syrte at obspm.fr, More Informations?
>     Note: use DNS for IP address.
> 
> If you have friends running Linux/Fedora exchange NTP privileges with each other!
> 
>