NOTIMP for unrecognized qtypes

[Peter Koch]

{this isn't really unbound specific}

On Thu, Jul 27, 2017 at 12:52:01PM -0700, Jacob Hoffman-Andrews via Unbound-users wrote:

> CAA. I believe it's the case that standards-conformant authoritative
> resolvers should return NOERROR for qtypes they don't recognize, rather

there are multiple functions for "name servers", but "authoritative
resolver" is just the one that doesn't exist -  see RFC 7719.

> than NOTIMP. Is this correct? If so, what is the relevant standard? I
> haven't been able to find a citation in
> https://tools.ietf.org/html/rfc3597,

RFC 3597 states

   To enable new RR types to be deployed without server changes, name
   servers and resolvers MUST handle RRs of unknown type transparently.

So, there is no special handling for unrecognized TYPEs (well, maybe
some meta QTYPE's are a necessary exception, but CAA would not fall
into this category).

-Peter