[Ntp] Finding leap-seconds.list

[Thomas Peterson <[e-mail]>]

As was discussed at the working group meeting at IETF 103 [0], I have decided to do some research on the leap-seconds.list file that the IETF appears to be hosting at https://www.ietf.org/timezones/data/leap-seconds.list, but for some participants of this working group appear unclear about.

Where is this referenced in an RFC or other IETF document?
I ran a search of “leap-seconds.list” across the spread of draft and RFC documents. No RFC that I have found makes direct reference. However, the current NTP BCP draft Section 4.6 [1] contains:

... SNIP ...

The IETF maintains a leap second list [[7]] for NTP users who are not
   receiving leap second information through an automatic source.

   Files are also available from other sources:

... SNIP ...

With [[7]] holding reference to the file hosted at, and a list of links to sources.

What else is www.ietf.org hosting of a similar nature?
This file alone is not the only thing hosted under www.ietf.org, in fact https://www.ietf.org/timezones/ directory listings show that all recent versions of the tzdb (including 2018g the most recent) which suggests a human maintaining the hosting of it, or automated process. Versions only go back to 2016. These files are also available over FTP [2].

How long have these files been hosted on www.ietf.org?
Internet archive's Wayback Machine [3] shows it appearing back in 2015.

Who is using the file?
ntpd does depend on it as was discussed at the WG meeting, [4]. FreeBSD [5] holds reference to it and users have reported issues when being unable to access it in the past. In addition, at least one library [6] make use of it outside of ntpd, however I don't believe this is heavily used or cause non-developers or system administrators any pain if it went missing.

Where else is this data hosted?
Mentioned in the draft NTP BCP referred above, NIST apparently also hosts the file [7] however at time of writing I'm unable to access it to verify it matches, in addition the US Naval Observatory hosts the file [8]. There was an email thread in 2016 [9] which discussed it, linking to these and other hosted versions. Many other FTP servers on the public internet appear to mirroring ftp.ietf.org which also includes this file and all of tzdb.

What have I not found?
How the hosting arrangement of tzdb on [ftp|www].ietf.org is managed - by whom, or what mailing list discussions or documents discussed its creation or maintenance. Nor have I found any information about how often the file is requested, however I'm sure a system administrator has that information somewhere.

I hope this email is a sufficient starting point for the discussion around the future hosting of this data by the IETF and would warmly encourage Paul Eggert [10] or anyone else with better memories (or Google-fu) to bring forward what they know.

Regards


[0] https://youtu.be/Qe9jhEAa4Wg?t=2735
[1] https://tools.ietf.org/html/draft-ietf-ntp-bcp-07#section-4.6
[2] ftp://ftp.ietf.org/iana-timezone/
[3] http://web.archive.org/web/*/https://www.ietf.org/timezones/data/leap-seconds.list
[4] https://support.ntp.org/bin/view/Support/ConfiguringNTP
[5] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213448
[6] https://www.npmjs.com/package/leap-seconds-list
[7] ftp://time.nist.gov/pub/leap-seconds.list
[8] ftp://tycho.usno.navy.mil/pub/ntp/leap-seconds.list
[9] https://mailarchive.ietf.org/arch/browse/ntp/?gbt=1&index=BPA3_2BJMS-TXHxhwfrbOkV4Y38
[10] https://mm.icann.org/pipermail/tz/2015-January/021986.html