[ntp:questions] Leap Second Handling

Martin Burnicki martin.burnicki at meinberg.de
Thu Nov 6 13:15:48 UTC 2008

PeterInFrankfurt at gmail.com wrote:
> Can anyone clarify how the leap second is supposed to work?
> We have a GPS receiver which, I understand, already receives the leap
> second indicator LI and knows the leap second will happen end of 2008
> UTC time.
> This GPS receiver speaks IRIG-B with IEEE 1344 extensions to our Time
> Server. IEEE 1344 definition says the Leap Second Pending is set in
> the 59 seconds before the leap second happens.
> So our Time Server will know nothing about the leap second until 59s
> before the year end. By which time, NTP propagation down through the
> stratum hierarchy will fail to notify all NTP clients before the year
> end.
> In this scenario is it necessary to manually insert the leap second
> into the Time Server?

You can download and install the NIST leap second file on your NTP server.

Be sure autokey is enabled since otherwwise the leap second file is not

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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