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

"Kurt Andersen (b)" <kboth@drkurt.com> Mon, 07 December 2020 21:56 UTC

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From: "Kurt Andersen (b)" <kboth@drkurt.com>
Date: Mon, 7 Dec 2020 13:55:29 -0800
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To: "Murray S. Kucherawy" <superuser@gmail.com>
Cc: John R Levine <johnl@taugh.com>, IETF DMARC WG <dmarc@ietf.org>
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Subject: Re: [dmarc-ietf] Ticket #1 - SPF alignment
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On Sun, Dec 6, 2020 at 11:13 PM Murray S. Kucherawy <superuser@gmail.com>
wrote:

> On Tue, Dec 1, 2020 at 2:17 PM John R Levine <johnl@taugh.com> wrote:
>
>> We would like to close this ticket by Dec 15, two weeks from now, so
>> short
>> trenchant comments are welcome.
>>
>> Ticket #1 is about SPF alignment.  We need to replace references to 4408
>> with 7408, ando clarify what if anything we do with SPF HELO checks if
>> the MAIL FROM is null.  One possibility is to say only MAIL FROM SPF
>> counts, if you want to align your bounces, sign them.  The other is to
>> explicitly say that HELO alignment is OK on bounces.
>>
>
> 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.

--Kurt