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Re: deprecating Postel's principle- considered harmful

Paul Wouters <paul@nohats.ca> Wed, 08 May 2019 14:11 UTC

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Date: Wed, 08 May 2019 10:11:03 -0400
From: Paul Wouters <paul@nohats.ca>
To: Dave Cridland <dave@cridland.net>
cc: Joe Touch <touch@strayalpha.com>, "ietf@ietf.org" <ietf@ietf.org>
Subject: Re: deprecating Postel's principle- considered harmful
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On Wed, 8 May 2019, Dave Cridland wrote:

> Sure about that?
> 
> From RFC 760:
> 
> That is, it should be careful to send well-formed datagrams, but should accept any datagram that it can interpret (e.g., not object to technical errors where
> the meaning is still clear).
> 
> The parenthetical example is explicitly stating that a datagram with a technical error should still be accepted.

Many UDP encapsulations of IP packets do not recalculate the outer UDP
checksum. It's a good thing we accept these datagrams with technical
errors.

Paul

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