Re: [Ntp] Resending: Thoughts on draft-ietf-ntp-refid-updates

[Martin Burnicki <[e-mail]>]

Tony Finch wrote:
> Martin Burnicki <[e-mail]> wrote:
>> Ask Bjørn Hansen wrote:
>>>
>>> If we had a formal (or informal) standard for distributing these
>>> offsets over DNS I’d be happy to help with that in my hobby project.
>>> We have a surprisingly robust shoe-string operated DNS infrastructure,
>>> and ~15 years later some amount of proven record. :-)
>>
>> Some years ago, Poul-Henning Kamp has already proposed to use DNS to
>> distribute leap second announcements and the current TAI offset. This is
>> much easier than distributing a leap second file and standard runtime
>> library calls can be used to implement this. The idea is to to let a
>> function like getaddrinfo() resolve a specific hostname, but don't
>> interpret the returned number as IPv4 address. Instead decode it in a
>> specific way to extract leap second information and TAI offset from the
>> returned bit pattern. See:
>>
>> 20151122 - Leapseconds via DNS
>> http://phk.freebsd.dk/time/20151122.html
> 
> I have a slightly different take on this idea: I distribute the complete
> leap second table at leapsecond.dotat.at in various formats including
> phk-style IPv4 addresses, human-readable IPv6 addresses, and a relatively
> terse TXT record. e.g.
> 
> $ dig +short leapsecond.dotat.at aaaa | sed 's/:6:/:06:/' | sort
> ::1972:06:30:23:59:60
> ::1972:12:31:23:59:60
> ::1973:12:31:23:59:60
> ::1974:12:31:23:59:60
> ::1975:12:31:23:59:60
> ::1976:12:31:23:59:60
> ::1977:12:31:23:59:60
> ::1978:12:31:23:59:60
> ::1979:12:31:23:59:60
> ::1981:06:30:23:59:60
> ::1982:06:30:23:59:60
> ::1983:06:30:23:59:60
> ::1985:06:30:23:59:60
> ::1987:12:31:23:59:60
> ::1989:12:31:23:59:60
> ::1990:12:31:23:59:60
> ::1992:06:30:23:59:60
> ::1993:06:30:23:59:60
> ::1994:06:30:23:59:60
> ::1995:12:31:23:59:60
> ::1997:06:30:23:59:60
> ::1998:12:31:23:59:60
> ::2005:12:31:23:59:60
> ::2008:12:31:23:59:60
> ::2012:06:30:23:59:60
> ::2015:06:30:23:59:60
> ::2016:12:31:23:59:60
> ::2019:06:27:23:59:59

This also sounds like a good idea, IMO.

The problem is that there is no progress in making things like this more
public. PHK has suggested this back in 2015 (IIRC), and I've heard
nothing else about this since.

If something like this should become a well accepted feature, there's
also the question who runs and maintains the top level DNS entry in a
reliable way? It must be made sure that the DNS entries are well
maintained and updated over a long time, not only for the next 2 years
or so, as long as some volunteers are interested in this topic.

Martin
-- 
Martin Burnicki

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