That's not really consistent with the DNS standards, and will break if you have
intermediate caching servers. Why? Because of this clause from RFC 2181:
Unauthenticated RRs received and cached from the least trustworthy of
those groupings, that is data from the additional data section, and
data from the authority section of a non-authoritative answer, should
not be cached in such a way that they would ever be returned as
answers to a received query.
It'll also, irrespective of caching, break DNSSEC.
What information are you trying to "piggyback" on responses to regular queries?
If it's a point-to-point thing, then create your own experimental record type,
or EDNS option (you already indicated you were willing to do modifications of
the BIND code and/or client-resolver code) in order to provide a "channel" for
this data between the client and its closest resolver. If it's an end-to-end
thing, understand that the authoritative nameservers "own" one end of that
transaction, and any attempts to manipulate the flow via an intermediate
device, reduces the integrity and trustworthiness of the data, making it look
like forgery, and possibly to the point where it gets rejected.
- Kevin
From: bind-users-boun...@lists.isc.org
[mailto:bind-users-boun...@lists.isc.org] On Behalf Of Jun Xiang X Tee
Sent: Wednesday, June 15, 2016 2:43 PM
To: bind-users@lists.isc.org
Subject: Append a Hard-coded Text Tuple into Additional Section of "dig" Feature
Dear members,
This is my first time posting a question to the mailing list. I am not sure
whether I should post my technical question to this list or not. If it is not,
I apologize for any inconvenience caused.
When I query for "google.com", the additional section returned is:
;; ADDITIONAL SECTION:
ns1.google.com. 200487 IN A 216.239.32.10
ns2.google.com. 197774 IN A 216.239.34.10
ns3.google.com. 246981 IN A 216.239.36.10
ns4.google.com. 193728 IN A 216.239.38.10
I wish to append a hard-coded text tuple into end of the section. An example
after the change is:
;; ADDITIONAL SECTION:
ns1.google.com. 200487 IN A 216.239.32.10
ns2.google.com. 197774 IN A 216.239.34.10
ns3.google.com. 246981 IN A 216.239.36.10
ns4.google.com. 193728 IN A 216.239.38.10
google.com 123456 IN TXT "some information that I
want to include"
I have searched through the code base for several days, but do not find a
good place to start with. Any suggestion? I am currently examining "resolver.c"
and "lookup.c" files. Thanks!
Regards,
Jun Xiang Tee
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