Re: [dmarc-ietf] Forensic report loops are a problem

John R Levine <johnl@taugh.com> Wed, 27 January 2021 18:38 UTC

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Date: 27 Jan 2021 13:38:08 -0500
Message-ID: <13f04f5a-4176-db79-ca4a-a99686e76edf@taugh.com>
From: "John R Levine" <johnl@taugh.com>
To: "Alessandro Vesely" <vesely@tana.it>, "IETF DMARC WG" <dmarc@ietf.org>
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Subject: Re: [dmarc-ietf] Forensic report loops are a problem
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On Wed, 27 Jan 2021, Alessandro Vesely wrote:
>> If the authentication is screwed up, sending a failure report is exactly 
>> the right thing to do.  That's what they're for.
>
>   Email streams carrying DMARC feedback data MUST conform to the DMARC
>   mechanism, thereby resulting in an aligned "pass" (see Section 3.1).

> Even if the screwed up message was a failure report itself?

Of course.  The failure repoort is a new e-mail message.  If it's not 
aligned, your code needs to be fixed.

> 3.3.  Transport
>
>   Email streams carrying DMARC failure reports MUST conform to the
>   DMARC mechanism, thereby resulting in an aligned "pass".  Special
>   care must be taken for authentication, as failure to authenticate
>   failure reports may result in mail loops.

Stop there.  If you don't want failure reports, don't send unaligned 
messages.

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