[Pool] Leap second configuration

Martin Burnicki martin.burnicki at meinberg.de
Fri May 29 09:04:40 UTC 2015

Hi Gábor,

Kiss Gábor wrote:
>> Last I used 4.2.6p5 was in 2012 and I'm now at ntpd 4.3.9.
> Unfortunately update is not an option.
>> Only config I have vs leap is same as in 2012:
>> leapfile /var/db/ntp/leap-seconds.list
> Yes, all newer NTP servers of us is configured such a way and
> they predict the next leap second well.
> However in this case the procedure is bit more complicated.

ntpd 4.2.6p5 should work fine with a proper, current leap second file.

What irritates me is that in your original email you wrote:

> However if you are interested in it, I can tell that the best result
> with the latest leap-seconds.3629404800 file and 4.2.6p5 is this:
> $ ntpq -c "rv 0 leap,tai,leapsec,expire" one_of_my_servers
> leap=00, expire=201505281348, leapsec=201501050000, tai=35
> $
> The expire value is the minute of restarting ntpd,
> and the leapsec was at 5th of January. That is strange...

There have been faulty 3rd party GPS receivers which started to announce 
a leap second shortly after the satellites started to broadcast the leap 
second information for June 30. For me this sounds like some software 
tool has generated the leap second file you are using to pass that 
announcement to ntpd.

On a system here, running 4.2.6p5 with the current leap second file from 
NIST, ntpq reports this, which looks more reasonable:

$ ntpq -c "rv 0 version,leap,tai,leapsec,expire"
version="ntpd 4.2.6p5 at 1.2349-o Mon Mar  9 16:31:26 UTC 2015 (1)", tai=35,
leapsec=201507010000, expire=201512280000

Can you send your leap second file to me and/or the list? Do you have a 
clue where that file comes from?

As mentioned in another post in this thread, ntpd sends the leap second 
warning to its clients only about 24 hours before the leap second occurs.


Martin Burnicki

Senior Software Engineer

MEINBERG Funkuhren GmbH & Co. KG
Email: martin.burnicki at meinberg.de
Phone: +49 (0)5281 9309-14
Fax: +49 (0)5281 9309-30

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