[Pool] Leap second is coming

Martin Burnicki martin.burnicki at meinberg.de
Wed Apr 15 11:37:16 UTC 2015

Kiss Gábor wrote:
> Hi guys,
> I just remind you there will be a leap second at the end of June.
> All of us should prepare of ntp pool servers as described here:
> http://lists.ntp.org/pipermail/questions/2008-August/019336.html

While it's generally a good idea to use a leap second file, the hints in 
the 2nd part of the referred email should be more appropriate for 
current installations running ntpd 4.2.6 or 4.2.8, i.e., use the 
"leapfile" keyword in ntp.conf.

Please note that if you run 4.2.6 with an outdated leap second file your 
NTP server will *not* accept any leap second warning from upstream 
servers or a refclock.

This is *not* a bug but the intended behavior. See NTP bug 861, comment 
46 and 47, as well as the following discussion:

So if you are running ntpd 4.2.6 with a leap second file configured then 
please make sure to use the current version of the leap second file. 
Otherwise you *will* encounter a problem when the leap second occurs.

BTW, in 4.2.8 this has fortunately been reworked, so an expired leap 
second file is ignored as it ought to be, and leap second announcements 
from other sources are accepted if the leap second file has expired.

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

Lange Wand 9, 31812 Bad Pyrmont, Germany
Amtsgericht Hannover 17HRA 100322
Geschäftsführer/Managing Directors: Günter Meinberg, Werner Meinberg, 
Andre Hartmann, Heiko Gerstung
Web: http://www.meinberg.de

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