[ntp:questions] ntpd: time reset problem

David Lord snews at lordynet.org
Mon Sep 14 23:31:03 UTC 2009

Unruh wrote:
> Steve Kostecke <kostecke at ntp.org> writes:
>> On 2009-09-14, David Lord <snews at lordynet.org> wrote:
>>> Steve Kostecke wrote:
>>>> On 2009-09-14, David Lord <snews at lordynet.org> wrote:
>>>>> Frank Elsner wrote:
>>>>> OT you also have rather a lot of sources specified and if just for a
>>>>> single box it seems a bit excessive and could be trimmed to four or
>>>>> five (I'd also guess some of those eight get same refid).
>>>> Red Herring.
>>> No, you missed the OT.
>> ???
>>>>> I've just been trying mobile broadband on a high latency connection
>> [snip]
>>>>> Then this weekend after reconfigured to use "burst" in server lines
>>>> The use of "burst" against other peoples' time servers is generally
>>>> considered to be abuse unless you have received permission to do so.
>> [snip]
>>> Anyway "burst" works and I now give myself permission to use
>>> "burst" to set time from my own ntp servers which is as good
>>> a compromise as any :-)
>> Great.
>>> Can you then suggest how it's at all possible for ntpd to be
>>> of any use on a mobile connection with such high latency?
>> Add to that the effects of aggressive power saving.
>>> I just need to get something working that's significantly
>>> better than wristwatch time.
>> Perhaps you need to choose a different tool.
> You could try chrony if you are running Linux or BSD. It might work
> better under your conditions. Your horrible latencies are worrysome, and
> make it hard to imagine how anything could work well. 

Seems to be a feature of the Vodafone system here. Punch a hole
through their network and latency will come down, that's why
'burst' works, just as explained in the documentation. Vodafone
have port and nat translation but users aren't assigned a single
ip address for a session so make several connections and it's
possible several ip addresses will be used.

Chrony gave a quicker convergence but doesn't seem to have
equivalent to 'ntpd -q' and I'm converging from many seconds
and even with the chrony equivalent of burst it takes too
long compared to using 'ntpd -q' to set time reasonably close.

On Ubuntu I can't get both chrony and ntpd to coexist from
package manager (conflicting packages).

Anyway method I'm using seems ok for now.




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