[ntp:questions] pruning the pool?

Rob nomail at example.com
Thu Jul 15 16:18:17 UTC 2010

hymie! <hymie at lactose.homelinux.net> wrote:
> Greetings.  I'm new here, so please be gentle.
> My servers are configured to use
> server 0.us.pool.ntp.org
> server 1.us.pool.ntp.org
> server 2.us.pool.ntp.org
> server 3.us.pool.ntp.org
> Through what I presume is a fluke of the DNS randomization, three of
> my four hosts were:
>    .INIT.          16 u  390  512    0    0.000    0.000 4000.00
>    .INIT.          16 u  378  512    0    0.000    0.000 4000.00
>    .INIT.          16 u  384  512    0    0.000    0.000 4000.00
> I tried searching the NTP web sites to figure out who maintains the NTP
> pools, and this was the best lead I got.  If these hosts are no longer
> offerring NTP, can they (and perhaps others in that same net block)  be
> removed from the pool?

Hosts that are not offering NTP are automatically removed from the pool.
Unfortunately, with (commonly used versions of) ntpd this DNS lookup
is only done when it is started.  So when you get 4 working NTP servers,
it may well happen that they stop offering NTP service later and you get
the above result.
It can be fixed by restarting ntpd.

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