[ntp:questions] ntpd wedged again

Dave Hart hart at ntp.org
Sun Feb 26 05:17:43 UTC 2012


On Sun, Feb 26, 2012 at 03:37, Danny Mayer <mayer at ntp.org> wrote:
> It could well be that rackety is sending KOD packets and this server is
> not recognizing them as such. rackety has a heavy load under normal
> circumstances so it may well do so. When it does so the ntp timestamps
> are going to be totally wrong, deliberately, so they should have been
> discarded immediately. I don't remember whether or not KOD had been
> introduced back when 4.2.2 was shipped so it may not be ignoring it when
> it should.
>
> I suggest you pick a different server with a more modern version of ntpd
> and see if that stabilizes the situation.

While I'm all in favor of running modern ntpd, it's not going to
affect KoD handling in terms of timekeeping.  KoD responses only occur
when a source IP exceeds relatively generous rate limits, and they
carry timestamps that are totally useless, deliberately, which is a
different beast than totally wrong.  KoD timestamps are set to match
the sender's originate timestamps, so if they attempt to use them for
time, they learn nothing their local oscillator wasn't already telling
them.

Cheers,
Dave Hart


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