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Re: [DNSOP] Draft mentioned in meeting re: fragmentation .

Paul Vixie <paul@redbarn.org> Thu, 21 November 2019 07:54 UTC

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From: Paul Vixie <paul@redbarn.org>
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Date: Thu, 21 Nov 2019 07:54:23 +0000
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Subject: Re: [DNSOP] Draft mentioned in meeting re: fragmentation .
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On Thursday, 21 November 2019 06:54:47 UTC Warren Kumari wrote:
> ...
> 
>  IP Fragmentation Considered Fragile
>                    draft-ietf-intarea-frag-fragile-17
> https://datatracker.ietf.org/doc/draft-ietf-intarea-frag-fragile/
> 
> 
> This is currently with the RFC Editor.

can someone who knows the rfc editor please tell them that the reference in 
this section is incorrect:

> 5.  Applications That Rely on IPv6 Fragmentation
> 
>    The following applications rely on IPv6 fragmentation:
> 
>    o  DNS [RFC1035]
>    o  OSPFv3 [RFC2328][RFC5340]
>    o  Packet-in-packet encapsulations

that's pretty accurate. RFC 1035 specified 512 octets as the maximum UDP 
payload, because adding UDP and IP headers, and IP options, yielded the 
largest IP datagram size that receivers were required to be able to reassemble 
if fragmentation occurred (576). in practice, this only happened on 
experimental links whose MTU might have approached the minimum (68).

in other words as much as i was stupid in EDNS for invoking fragmentation, it 
was technically permitted by DNS itself, though in practice, not used before 
EDNS.

-- 
Paul

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