[LEAPSECS] Time Synchronization in Financial markets

[Martin Burnicki]

Hal Murray wrote:
> 
> imp at bsdimp.com said:
>> Except, last I checked, NTP doesn't use this. And applications don't re-read
>> the zone file info when they are updated, so long running applications will
>> use the old data. Also, that file doesn't have then pending leap second this
>> December in it since the date is too old. 
> 
> ntp has code to read that file.  It takes a
>   leapfile <filename>
> in your ntp.conf
> 
> 
> If it's time for a new one, ntpd checks for a new version every 24 hours.

Yes, but only ntpd 4.2.8 does so, and re-reads an updated file
automatically.

Earlier versions didn't re-read the file. You had to restart ntpd. Also,
ntpd 4.2.6 accepts a leap second file even if it is expired. This was
intentional by Dave Mills. As a consequence this means that ntpd 4.2.6
will *not* handle a leap second even though an upstream NTP server or a
GPS refclock provides a valid announcement, if ntpd has been provided
with an outdated leap second file.

Martin