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

Alessandro Vesely <vesely@tana.it> Wed, 27 January 2021 09:49 UTC

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From: Alessandro Vesely <vesely@tana.it>
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Date: Wed, 27 Jan 2021 10:49:02 +0100
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Subject: Re: [dmarc-ietf] Ticket #1 - SPF alignment
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On Tue 26/Jan/2021 23:36:19 +0100 Scott Kitterman wrote:
> On Tuesday, January 26, 2021 11:47:51 AM EST Alessandro Vesely wrote:
>> On Tue 26/Jan/2021 14:14:45 +0100 Scott Kitterman wrote:
>>> On Tuesday, January 26, 2021 6:54:56 AM EST Alessandro Vesely wrote:
>>>> 
>>>> I doubt that SPF filters report envelope-from=postmaster@HELO; more 
>>>> likely they write helo=HELO.  In that case, the paragraph quoted above
>>>> is deceptive. >>>>
>>>>> I believe the proposed text is clear enough about not using
>>>>> separate HELO identity results and that's appropriate. >>>>
>>>> My filter collects SPF results recorded from an upstream SPF filter.
>>>> It writes Received-SPF: lines for each identity.  For NDNs, it writes
>>>> a Received-SPF: for the HELO identity only.  Am I allowed to use that 
>>>> result for DMARC? >>>
>>> No.  You should only use Mail From results.
>> 
>> So NDNs having only an aligned HELO will never pass DMARC?
>> 
>> And what is a <scope>helo</scope> element in aggregate reports provided for?
>> 
>> The spec says:
>> 
>>           [SPF] can authenticate either the domain that appears in the
>>     RFC5321.MailFrom (MAIL FROM) portion of [SMTP] or the RFC5321.EHLO/
>>     HELO domain, or both.
>> 
>> And then:
>> 
>>     In relaxed mode, the [SPF]-authenticated domain and RFC5322.From
>>     domain must have the same Organizational Domain.  In strict mode,
>>     only an exact DNS domain match is considered to produce Identifier
>>     Alignment.
>> 
>> So, consider the following message without DKIM signatures:
>> 
>> HELO example.org
>> MAIL FROM:<user@example.com>
>> 
>> Received-SPF: pass (domain example.org
>>    designates 192.0.2.1 as permitted sender)
>>    identity=helo; helo=example.org;
>> Received-SPF: fail (domain of user@example.com
>>    denies 192.0.2.1 as permitted sender)
>>    identity=mailfrom; envelope-from="user@example.com".com";
>> Subject: Not using a mail client for this example
>> From: different-user@example.org
>> 
>> Does it pass DMARC?
> 
> No.


Let's not be silly, Scott.  We have example.org as the SPF-authenticated domain 
and it is aligned with From:.  Are you saying that the message would pass if it 
had an empty bounce address, but since it can bounce it does not pass?!?


Best
Ale
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