[ntp:questions] Pool server gone wild

Roger invalid at invalid.invalid
Fri Feb 20 11:31:18 UTC 2015


On Fri, 20 Feb 2015 10:15:31 +0100, Terje Mathisen
<terje.mathisen at tmsw.no> wrote:

>Rob wrote:
>> Roger <invalid at invalid.invalid> wrote:
>>>      http://www.pool.ntp.org/scores/90.155.73.34
>>>
>>> How does one alert an operator that their server is sick?
>>> Checking back through my peerstats I see that last entry
>>> which was okay was 2015-02-16 15:08:56.
>>
>> There is no need.  The pool system has sent a mail to the operator
>> and when he apparently does not react it is not a problem because
>> the server will have been removed from the pool anyway.
>>
>You are of course correct, I would just add a single small caveat:

OK, Rob, thanks for that.

>If you are using an older version of ntpd which doesn't support the pool 
>directive, then you would be stuck trying to access such a server until 
>you restart ntpd.
>
>With something like 'pool pool.ntp.org' in your ntp.conf file the ntpd 
>process will pick the first N (10) servers returned from DNS, then once 
>every hour it will redo the DNS lookp, the two worst-performing current 
>servers will be removed and a pair of new ones will be used to replace them.

I'm using 4.2.8p1 (compiled using gcc 4.8.2 and binutils 2.23,
if those are important) and "pool uk.pool.ntp.org" as the only
selection line.

The server was still in the peerstats at 18:25 the following day
when I did a reboot. So, after approximately 27 hours, ntpd
hadn't dropped it. Obviously, my system isn't performing as you
say it should. Can you, or anyone else, provide a clue as to how
I might determine if my system is a fault or if there is a bug
in the ntpd code?

>I.e. as long as you use the pool properly there is no need to worry 
>about servers coming and going, or even individual servers that become 
>falsetickers.

When I first tried 4.2.8 I noticed the "soliciting" lines and
that occasionally a server didn't get used. I've never noticed
ntpd dropping a server once it had started using it but this is
the first time that a server has been so obviously wrong that I
would have wanted it dropped/replaced.
-- 
Roger



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