Re: Last Call: <draft-ietf-dmarc-interoperability-15.txt> (Interoperability Issues Between DMARC and Indirect Email Flows) to Informational RFC

"John Levine" <> Sun, 22 May 2016 03:05 UTC

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Date: Sun, 22 May 2016 03:05:34 -0000
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From: John Levine <>
Subject: Re: Last Call: <draft-ietf-dmarc-interoperability-15.txt> (Interoperability Issues Between DMARC and Indirect Email Flows) to Informational RFC
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>>    [RFC6377] provides some guidance on using DKIM with Mailing lists.
>>    The following mitigation techniques can be used to ease
>>    interoperability issues with DMARC and Mailing lists:
>It should probably be indicated whether these techniques would be applied
>to all messages, or only to messages sent from domains with a DMARC
>policy other than "p=none". (I prefer the latter.)

It's an implementation issue, depending on whether the list software
can get the DMARC policy from a DNS query or from an
Authorization-Results header.  My MTA puts an A-R header on incoming
mail so I have a shim after the list manager that looks at the A-R
header and rewrites the From: address (into addresses,
which some people imagine are not deliverable) if it sees a DMARC

>>    o  Configuring the MLM to "wrap" the message in a MIME message/rfc822
>>       part and to send as the Mailing List email address.  Many email
>>       clients (as of the publication of this document), especially
>>       mobile clients, have difficulty reading such messages and this is
>>       not expected to change soon.
>This seems like a quite elegant solution. I'm very surprised by the second
>sentence - are these clients that have difficulty with many Content-Types
>or is it a specific issue for message/rfc822?

It's a one-entry MIME digest, so it looks like a digest, not an
individual message.