Re: [DNSOP] More work for DNSOP :-)

Andrew Sullivan <> Sat, 07 March 2015 00:47 UTC

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Date: Fri, 06 Mar 2015 19:47:31 -0500
From: Andrew Sullivan <>
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Subject: Re: [DNSOP] More work for DNSOP :-)
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On Fri, Mar 06, 2015 at 01:37:17PM -0800, Paul Vixie wrote:
> nothing prevents a server from answering A with AAAA as additional data,
> or answering AAAA with A as additional data.

I seem to recall having this discussed at length more than once in
DNSEXT, and the conclusion was always that the additional complication
wasn't worth the effort.  If a cache had an A but not AAAA or
conversely (a situation likely to happen), then there'd be no win
because you'd have to ask again anyway.  Moreover, you couldn't even
tell whether you didn't get the thing you wanted because it wasn't in
cache or because it didn't exist, so you'd end up asking more often
than you wanted.  And because application developers would need to
handle all these cases anyway, the workflow would be more complicated.
(Simplification of the workflow seemed to be the main driver in the
past.  Maybe latency would now trump that, but I actually am not
convinced this would lower latency as opposed to popping off queries
in parallel anyway.)

So it didn't seem to be worth it, at least the last time.  I'm not
able to put my hands on those discussions at the moment, which makes
me think it probably happened on namedroppers@ and not on dnsext@.


Andrew Sullivan