[ntp:questions] NTPd instability and openntpd

Danny Mayer mayer at ntp.isc.org
Sun Sep 16 02:27:25 UTC 2007


Mij wrote:
> I submitted to pool.ntp.org with a stratum 2 NTPd server. The useful
> system scoring however shows me significant discontinuity in the
> service:
> 
> http://www.pool.ntp.org/scores/81.208.58.150
> 
> The host is a dual processor FreeBSD host with low load, today
> counting 107 days of uptime. The connectivity is a 11Mbps fiber optic,
> that proven pretty reliable in the last five years.
> So I did not believe those stats first and put a polling script on
> another server 150 km away from this one. Unfortunately or not, it
> confirmed the downtimes.
> 
> So NTPd seems the only point of guilt. I re-compiled with debugging
> enabled to trace the problem. I could be unable to read its debugging
> dumps, but its L1 and L2 debug levels proven useless to me. For
> example, none did show client request coming in, nor served nor
> rejected. L1 is quite a lot verbose and L2 is extremely verbose, so
> further levels would be simply unreadable to me.
> 

There is no such thing as L1 and L2 in ntpd (at least the reference
implementation). What version are you running? You run debug mode by
adding the -D2 or -d arguments to the command line. Please post the
output of ntpq -p, your config file and the command-line arguments. It's
hard to determine what's wrong without any information. Also post
anything logged in your syslog which might show what's going on.

> NTPd is not under explicit ulimit. Confs are nearly freebsd's defaults
> (5 servers are used and some statistics are enabled).
> 
> In favour of sparing some time I tried possible alternatives. I see
> OpenNTPd favourably, as openbsd's software typically works simply and
> well. But I see some (old, not up to date) criticism on its precision
> and stuffing an imprecise server into the pool would be quite
> unethical.
> 

There are issues with OpenNTPd and I believe it does not support mode 6
packets which is required to run ntpq against it. In addition it is not
an NTP server but an SNTP server.

Danny



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