Re: [DNSOP] On some terminology in draft-ietf-dnsop-respsize (truncation)

Paul Vixie <> Mon, 03 March 2014 18:46 UTC

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Date: Mon, 03 Mar 2014 10:46:25 -0800
From: Paul Vixie <>
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Subject: Re: [DNSOP] On some terminology in draft-ietf-dnsop-respsize (truncation)
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David Conrad wrote:
> On Mar 3, 2014, at 3:14 PM, Paul Vixie <
> <>> wrote:
>> are you advising (by implication) that a receiver who hears TC=1 with
>> ANCOUNT>0 or NSCOUNT>0 or ADCOUNT>0 treat it as a FORMERR?
> Hmm.
> I always assumed that if TC=1, pretty much everything else in the
> response was irrelevant since I would be unable to trust what was
> there was complete. So I'd say 'no' and I don't see any ambiguity....

i know of code that's in widespread use which assumes that TC=1 means
that the last non-empty section was damaged but that it is safe to cache
anything found in earlier sections. this code is clearly wrong-headed,
but as i said, is in wide-spread use.

a protocol clarification (not a change, which dnsop can't by charter
make) might be that a sender should send empty response, authority, and
additional sections when setting TC=1, and that a receiver must act as
if the response, authority, and additional sections are empty if it sees