Folks, I've just checked some of the commonly known sources for the leap second file to be used with NTP and found that some sites on the internet only provide outdated versions of the leap second file. Some of the files will expire on 28 December 2015. So if you have an NTP daemon running and a leap second file specified in the ntp.conf file you should check if you have a current copy of the file installed, or otherwise update the leap second file. Unlike earlier version of ntpd (up to 4.2.6*), current versions (4.2.8*) of the NTP daemon really evaluate the expiration date of the file, and don't accept outdated an outdated leap second file. For many NTP installations this doesn't really matter, but - if an applications expects a current TAI offset set in the OS kernel then it won't get the correct information without a valid leap second file - if a valid leap second file is available then the leap second information takes precedence over leap second announcements from upstream servers, etc., so a valid leap second files provides some protection against wrong leap second announcements from faulty upstream servers. The original leap second file from NIST is available via this link: ftp://time.nist.gov/pub/leap-seconds.3629404800 (current) ftp://time.nist.gov/pub/leap-seconds.list (link to current) and the current version expires 28 June 2016. However, unfortunately the NIST server is often not reachable. The IERS which decides whether a leap second is to be scheduled or not, is now also providing an own leap second file: https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.3651350400 (current) https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list (link to current) However, this file already expires on 28 January 2016, which is pretty early. I've already contacted the folks at IERS and asked them to set the expiration date to shortly before the next leap second event. I guess they will provide a new leap second file shortly after the next bulletin C has been published in January 2016. The USNO formerly also provided an own version of a leap second file via ftp://tycho.usno.navy.mil/pub/ntp/ However, on this web page there is only an outdated copy of the IERS file now, which expires on 28 December 2015. I've already tried to contact the folks at USNO and asked them to update their server, but haven't received a reply, yet. A copy of the current leap second file can also be found in the current Time Zone data package provided by the IANA. Since the IETF web site provides an unpacked copy of the tzdata archive the NIST file is also available here: http://www.ietf.org/timezones/data/ http://www.ietf.org/timezones/data/leap-seconds.list (shipped with tzdata, copy of a NIST file) Since this is a copy of the current NIST file this file is valid until 28 June 2016. Another copy of the current NIST leap second file is available via the Meinberg web site: http://www.meinberg.de/download/ntp/leap-seconds.list Hope this helps. Martin -- Martin Burnicki Senior Software Engineer MEINBERG Funkuhren GmbH & Co. KG Email: martin.burnicki@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