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Re: [dnsext] [Technical Errata Reported] RFC4343 (6361)

Evan Hunt <each@isc.org> Mon, 28 December 2020 18:42 UTC

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Date: Mon, 28 Dec 2020 18:42:05 +0000
From: Evan Hunt <each@isc.org>
To: Kaspar Etter <me@kasparetter.com>
Cc: Donald Eastlake <d3e3e3@gmail.com>, Eastlake III Donald-LDE008 <Donald.Eastlake@motorola.com>, IETF DNSEXT WG <dnsext@ietf.org>, Erik Kline <ek.ietf@gmail.com>, "Eric Vyncke (evyncke)" <evyncke@cisco.com>, Olafur Gudmundsson <ogud@ogud.com>, RFC Errata System <rfc-editor@rfc-editor.org>
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Subject: Re: [dnsext] [Technical Errata Reported] RFC4343 (6361)
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On Wed, Dec 23, 2020 at 09:51:25AM +0100, Kaspar Etter wrote:
> Thanks a lot for the quick reply. Just to make sure that there’s no
> misunderstanding: If I figured it out (i.e. I should receive the
> capitalization of the label as it is in the server’s database in DNS
> responses), then the deployed DNS DOESN’T conform to this RFC.
> Examples:
> dig IETF.org <http://ietf.org/> => IETF.org <http://ietf.org/> in the answer section of the DNS response
> dig ietf.org <http://ietf.org/> => ietf.org <http://ietf.org/> in the answer section of the DNS response

This has been ambiguous for a long time.  If you check the authoritative
servers for ietf.org, the answer section is capitalized as specified in
the zone database, not matching the question:

   $ dig +noall +answer @ns1.ams1.afilias-nst.info. IETF.org
   ietf.org.		1800	IN	A	4.31.198.44

However, some servers use case-insensitive name compression in their
responses. Differently-capitalized versions of the same name are treated as
duplicates, so if IETF.org appears in the question section, the answer
section will refer back to that.  In my view, this behavior is incorrect,
but it's commonplace.

I'm not sure whether this helps with the issue at hand, I just thought
the additional context might be useful.

-- 
Evan Hunt -- each@isc.org
Internet Systems Consortium, Inc.

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