[dns-operations] extra records in resolver answer, any benefit?

Tony Finch dot at dotat.at
Tue Jan 27 10:25:07 UTC 2015

bert hubert <bert.hubert at netherlabs.nl> wrote:
> It is all optional, and nobody does anything with that data. In fact stub
> resolvers do very little with what they receive. So for example, even the
> additional processing for an MX record is completely ignored mostly.


The difficulty with MX (and SRV) additional data is that you don't get a
clear indication whether the target address records are nonexistent or
just unavailable, so it tends to be easier to look them up regardless of
the contents of the additional section.

f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
Shannon: Southwest 5, increasing 6 or 7, then veering west 7 or gale 8,
occasionally severe gale 9 later. Rough, becoming very rough or high.
Occasional rain, showers later. Moderate or good, occasionally poor.

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