Subject: Retrieve RRs from the authority and additional sections

Retrieve RRs from the authority and additional sections

From: Tobias Nießen <>
Date: Sun, 30 Jul 2017 00:47:29 +0200


as discussed at, we are
wondering how difficult it will be to allow users to access resource
records in the "authority" and "additional" sections of DNS messages.
Even though c-ares does not appear to provide an API to access them
directly, it should be possible to implement this without too many
problems on our side using existing c-ares functions, adig.c contains
good examples. However, it was suggested to provide an API upstream.
Does such an API exist, was one considered in the past, or would a PR at
GitHub (generally) be accepted?

I could not find any information about the kind of RRs permitted in
those sections. I have never seen other records than NS records in the
authority section, but that surely does not mean that it is impossible
(or invalid) to send other record types as part of that section.
Similarly, I don't know anything about the constraints of RRs in the
additional section, and would be glad if someone could give me (and us)
some insights, or maybe a reference to a specification (RFC 1035 does
not appear to cover this).

Tobias Nießen
Received on 2017-07-30