Re: [dmarc-ietf] Spirit of RFC8601 section 5 for invalid A-R headers

John R Levine <johnl@taugh.com> Fri, 03 April 2020 20:30 UTC

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Date: 3 Apr 2020 16:30:09 -0400
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From: "John R Levine" <johnl@taugh.com>
To: "Kurt Andersen (b)" <kboth@drkurt.com>
Cc: "dmarc@ietf.org" <dmarc@ietf.org>, "Brandon Long" <blong@google.com>
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Subject: Re: [dmarc-ietf] Spirit of RFC8601 section 5 for invalid A-R headers
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>>> In practice, I don't know how common it is for clients to consume this
>>> header.
>>
>> They have to if they're adding ARC seals on the way out.
>
> Only if the ADMD's particular implementation to pass through the
> information from incoming perimeter system to outgoing perimeter system
> happens to utilize the A-R header(s) for the purpose of conveying that
> information.

It would seem pretty perverse to create an AAR header with exactly the 
same info as the AR header by ignoring the AR header.  But whatever.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly