[ntp:questions] all servers rejected

Marton Fabo mortee at ntp.isc.org
Fri May 18 01:54:42 UTC 2007


Per Hedeland wrote:
> Well, ntpd wasn't designed to operate under the extreme - or rather
> broken - conditions that you have, so you'll have to do a bit of
> tinkering, and it may not work anyway. First of all a drift of 1 hr per
> 24 hrs is 41667 ppm, which is of course way beyond the 500 ppm limit
> under which ntpd can keep time by slewing only, so at best you would get
> recurring backward steps of the clock.

Well, actually that wouldn't be such a big problem, if it could be kept
to reasonably small steps back in time. By this I mean that it remains
on the order of a at most a few minutes - I'm trying to do some
development work on that damned linux, and make always gets confused
when it sees files with mod times way into the future after me getting
upset by the wrong clock and reseting it manually. Even worse, I access
the sources from the host machine too, so it gets even more confused too
as it sees its own clock and the crazy timestamps on the files.

> In any case having such a list of servers inside a vmware instance is
> pretty bizarre - bothering stratum 1 and 2 servers on the Internet all
> over Europe with the timekeeping on your virtual machine is rude if
> nothing else. It should be quite sufficient to use the vmware host as
> server - drop everything else, including the local clock which is
> entirely pointless in this scenario. This could actually make things
> work at least to the point where ntpd can consider stepping your clock,
> since one problem is that it can't find any particular server to believe
> given those varying offsets, and hence doesn't know what time to step it
> to.

OK, what you write makes sense pretty much. I tried to exclude anything
except my own server, but it still doesn't get selected. For some time
ntpq reported it having jitters on the order of 10 seconds, then it
reverted to refid .INIT., stratum 16 and a fixed 4 seconds jitter. I'm
not sure I inderstand what this means...

mortee




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