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

bert hubert bert.hubert at netherlabs.nl
Tue Jan 27 09:45:26 UTC 2015

On Tue, Jan 27, 2015 at 10:07:33AM +0100, Marek Vavruša wrote:
> Hi, I was wondering if there's any operational benefit in including
> records other than direct answer in resolver responses [1]?  For
> example, some recursors return authoritative NS records, SOA, glue,
> etc., and some servers scrub them. I have utterly failed in finding
> anything in the related RFCs to back this up, so I guess it's up to
> implementors.

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.

> congested mobile networks, it makes sense to me to return only minimal
> possible responses.
> Or am I wrong?

It also saves CPU for the resolver.


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