Re: [DNSOP] I-D Action: draft-ietf-dnsop-avoid-fragmentation-00.txt

Mukund Sivaraman <muks@mukund.org> Wed, 08 July 2020 15:18 UTC

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From: Mukund Sivaraman <muks@mukund.org>
To: Marek Majkowski <majek04@gmail.com>
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Subject: Re: [DNSOP] I-D Action: draft-ietf-dnsop-avoid-fragmentation-00.txt
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On Wed, Jul 08, 2020 at 04:50:30PM +0200, Marek Majkowski wrote:
> > The maximum buffer size offered by an EDNS0 initiator SHOULD be
> > no larger than the estimated maximum DNS/UDP payload size...
> 
> This seems to indicate that EDNS0 over TCP should have a small buffer
> size as well. Consider wording like "...buffer size offered by an
> EDNS0 initator over UDP...".

The field has no effect in DNS over TCP. The EDNS "requestor's UDP
payload size" field that is encoded in the CLASS field of the OPT RR is
only used for DNS responses over UDP. It is ignored for DNS over TCP.

		Mukund