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

Alessandro Vesely <> Tue, 02 February 2021 11:59 UTC

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To: John Levine <>,
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From: Alessandro Vesely <>
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Subject: Re: [dmarc-ietf] Ticket #1 - SPF alignment
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On Tue 02/Feb/2021 00:11:54 +0100 John Levine wrote:
> In article <> you write:
>>On Mon 01/Feb/2021 01:10:01 +0100 Scott Kitterman wrote:
>>> SPF is what it is (RFC 7208).  DMARC doesn't need to re-invent the protocol
>>> (and shouldn't).  For any properly implemented SPF verifier, DMARC should be
>>> able to consume the Mail From result.
>> Perhaps Courier-MTA is not so properly implemented, but when mail from is empty 
>> it just omits the corresponding Received-SPF: header field.
> That's a peculiarity of Courier.

Yes.  Configured as at mine, it writes three Received-SPF: fields, for helo, 
mfrom, and, as a non-standard extension, for From:.  As I said, the one for 
mfrom is only written in case mfrom is not-empty.

> My MTA adds an SPF clause in the A-R header whether or not there's a null
> bounce address.

How can it report, say, fail for helo and pass for mfrom in just one clause?

>> OTOH, properly implemented SPF verifiers could skip producing a Mail From 
>> result if the helo identity was verified successfully.
> No, they could not.  That's not what the SPF spec says.

                                If a conclusive determination about the
    message can be made based on a check of "HELO", then the use of DNS
    resources to process the typically more complex "MAIL FROM" *can* be
                         (my emphasis)