Re: [gpsd-dev] Clarifications needed for the time-service HOWTO

[Eric S. Raymond]

Hal Murray <address@hidden>:
> 
> address@hidden said:
> > # ntptrace ntp.ubuntu.com
> > 91.189.89.199: timed out, nothing received
> > ***Request timed out
> 
> > They seem to be down.
> 
> No, the servers are OK.  The problem is a buggy tool and/or a poor choice of 
> tool.  Try sntp -d xxx or ntpdate -d xxx  (ntpdate is depricated)
> 
> ntptrace calls ntpq which uses mode 6 packets.  That's the back door for 
> debugging/monitoring.  It's disabled (from the outside world) on many/most 
> ntpd servers that are exposed to the big/bad internet.  But when it works, it 
> gives text printout which is easier to parse from simple scripts.

Would you please expand this into a brief discussion of NTP diagnostic tools 
for the HOWTO?

There's a new section that begins thus:

== NTPD performance tuning ==

For good time stability, you should always have at least two other
reference clocks in your ntpd.conf besides your GPS - in case, for
example, your GPS is temporarily unable to achieve satellite lock.

TODO: more on performance tuning and diagnostics here. 

This is where we need to talk about (a) adusting fudges, and (b) how
to check the quality of your chimers.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>