[ntp:questions] Very rapid polling

jlevine jlevine at boulder.nist.gov
Tue Feb 10 14:39:15 UTC 2009

On Feb 9, 8:26 pm, ma... at ntp.isc.org (Danny Mayer) wrote:
> jlevine wrote:
> > In the last few days I have seen an increasing number of systems that
> > are requesting the time in NTP format several times per second. This
> > poll interval is far in excess of the usual best practices. Since
> > there are a number of such systems, it is possible that this problem
> > is a result of a new version of NTP that has just been released.
> > Please let me know if you have any information about a new version of
> > NTP that can do this or if any of you are seeing the same problem.
> > Thanks.
> > Judah Levine
> > Time and Frequency Division
> > NIST Boulder
> Hi Judah,
> There is no new release yet (the 4.2.4p6 was just a patch release to fix
> a couple or minor issues mainly related to OpenSSL. It is most unlikely
> that ntp is doing this. Did you take a couple of the addresses and query
> them with ntpq? I don't think that ntpd can be configured to query that
> quickly. Harlan is preparing a new stable release from the development
> branch. Dave has added KOD code to deal with situations like this and
> such clients are likely to find their clock drifting off if the do not
> follow the protocols.
> Danny

   I have the ip addresses that are causing the problems. I have not
the ISPs because my previous experience is that they are very
unhelpful in
dealling with these sorts of queries. However, the sources are
addresses, so perhaps there is a chance.
   I was pretty sure that this was not caused by a bug in a new
version of
NTP, but I just wanted to check for sure. (I remember that some older
of Linux could use a poll interval of 0 by default, but that was a
long time ago.)
These sorts of problems come and go on all of our servers pretty much
all of
the time. Most of them are just annoying, but this one is serious
enough to
cause possible trouble.

Thanks for your prompt replies.

Judah Levine
Time and Frequency Division
NIST Boulder

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