[time-nuts] On the IETF leap-seconds.list SHA1

Martin Burnicki martin.burnicki at burnicki.net
Wed Dec 20 08:50:05 EST 2017


John Hawkinson wrote:
> Umm, the presence of a copy of the IANA TZ distribution at https://www.ietf.org/timezones/ is not evidence of an "IETF leap-seconds list." This is bizarre, and probably a web server configuration error that even exists. The IETF is not involved in this list. I guess this shows why Google is an unreliable indicator of authority.
> 
> https://www.ietf.org/timezones/data/leap-seconds.list
> is not a URL anyone should be depending on.
> 
> https://data.iana.org/time-zones/code/leap-seconds.list
> is perhaps a better URL for the file in the tz distribution, but I'd hestitate to call it canonical. Start at https://www.iana.org/time-zones.
> 
> But then the tz database isn't an authorative source, either. Per the NEWS file:
> 
>     The 'leapseconds' file is now generated automatically from a
>     new file 'leap-seconds.list', which is a copy of
>     <ftp://time.nist.gov/pub/leap-seconds.list>.
>     A new source file 'leapseconds.awk' implements this.
>     The goal is simplification of the future maintenance of 'leapseconds'.
> 
> That is, it's just a copy of NIST's file.

In fact, when NIST or IERS have provided a new leap-seconds.list file
then it is picked up somewhat later by the TZ database maintainers, and
updated in the TZ database.

The IERS page only provides the content of the last recently released TZ
database package, so the updated leap-seconds.list file will only appear
on the IERS page after a new version of the TZ database has been
released, whenever that happens.

So there may be a significant delay until an updated leap-seconds.list
file becomes available at the IETF web site, and I strongly suggest to
pick that file up from either
ftp://time.nist.gov/pub/leap-seconds.list

or
https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list

See also a summary at
https://www.meinbergglobal.com/download/burnicki/the_ntp_leap_second_file.pdf

Martin


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