Re: [DNSOP] New Version Notification for draft-sury-deprecate-obsolete-resource-records-00.txt

Evan Hunt <each@isc.org> Mon, 26 March 2018 12:45 UTC

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Date: Mon, 26 Mar 2018 12:45:44 +0000
From: Evan Hunt <each@isc.org>
To: =?utf-8?B?T25kxZllaiBTdXLDvQ==?= <ondrej@isc.org>
Cc: Paul Hoffman <paul.hoffman@vpnc.org>, dnsop <dnsop@ietf.org>
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Subject: Re: [DNSOP] New Version Notification for draft-sury-deprecate-obsolete-resource-records-00.txt
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On Mon, Mar 26, 2018 at 02:09:14PM +0200, Ondřej Surý wrote:
> That’s one of the goals of the document - saying: “it’s ok to not
> implement those RR Types, and it’s ok to break if you receive them"

We need to state clearly what is meant by "ok to break".

I described my preferred approach as an implementer upthread. Let me
state it again more formally and let people knock it down:

0. types will be flagged as obsolete/deprecated in the IANA registry,
   and the following guidance is given to DNS implementors in the handling
   of obsolete/deprecated RR types:

1. auth servers SHOULD log a warning when loading zones that contain
   obsolete/deprecated rrtypes.

2. responders SHOULD NOT compress rdata when rendering obsolete/deprecated
   type records to wire format.

3. queriers which receive obsolete/deprecated type records MAY interpret
   them as unknown type records (rfc 3597), and MUST NOT interfere with
   their transmission.

   3a. note that the choice to parse obsolete/deprecated MAY be contingent
       on whether the rdata is compressed: an obsolete type record MAY be
       parsed as a known type if its rdata is uncompressed, but as an
       unknown type otherwise.

4. validators and signers SHOULD treat rdata for obsolete/deprecated types
   as opaque with respect to canonical RR ordering and deduplication

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