Re: [dmarc-ietf] Ticket #1 - SPF alignment

John Levine <johnl@taugh.com> Mon, 07 December 2020 22:13 UTC

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Date: 7 Dec 2020 17:13:44 -0500
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From: "John Levine" <johnl@taugh.com>
To: dmarc@ietf.org
Cc: kboth@drkurt.com
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Subject: Re: [dmarc-ietf] Ticket #1 - SPF alignment
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In article <CABuGu1prNdJKP_-2yv7NbnbVH340D75PPxKmeDTHEd8qG+0RtQ@mail.gmail.com> you write:
>> I have a slight preference for the first option.  HELO is too arbitrary in
>> the protocol for me to put much value in using it in any of these systems.
>
>There's a bit of an implementation detail though. If one is relying on an
>encapsulated ck_host() function then you may not know whether it checked
>the HELO or the MAIL FROM. Imposing a requirement like this from DMARC
>seems like it verges on a layering violation.

You should be able to look at the bounce address and if it's null,
skip the SPF check.  No need to peek inside SPF for that.

R's,
John