Re: [dmarc-ietf] Sender vs From Addresses

Gren Elliot <gelliot@mimecast.com> Wed, 24 March 2021 20:37 UTC

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From: Gren Elliot <gelliot@mimecast.com>
To: "Kurt Andersen (b)" <kboth@drkurt.com>, John Levine <johnl@taugh.com>, "dmarc@ietf.org" <dmarc@ietf.org>
Thread-Topic: [dmarc-ietf] Sender vs From Addresses
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Date: Wed, 24 Mar 2021 20:37:00 +0000
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Subject: Re: [dmarc-ietf] Sender vs From Addresses
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Calconnect’s TC-CALSPAM group is currently looking at this issue and yes, the reason is because of real world corporations that use multiple brands with different domains.  Typically employees got a single email address on one of their domains but often work with people who have email addresses in different domains.

From: "Kurt Andersen (b)" <kboth@drkurt.com>
Date: Wednesday, 24 March 2021 at 20:27
To: John Levine <johnl@taugh.com>
Cc: "dmarc@ietf.org" <dmarc@ietf.org>rg>, Gren Elliot <gelliot@mimecast.com>
Subject: Re: [dmarc-ietf] Sender vs From Addresses

On Wed, Mar 24, 2021 at 1:21 PM John Levine <johnl@taugh.com<mailto:johnl@taugh.com>> wrote:
It appears that Gren Elliot  <gelliot@mimecast.com<mailto:gelliot@mimecast.com>> said:
>For better or worse, there is long established practice in the Calendaring community when implementing iMIP (rfc6047) when an
>assistant is working on behalf of a manager for the manager’s email address to populate the “From:” header and the
>assistant’s email address to populate the “Sender:” header.

DMARC only looks at the domain part of the From header.  How often do the manager and assistant have e-mail addresses that
are not in the same domain?

John,

This goes back to your Roman Empire scenario. It's not necessarily common, but it isn't unheard of for domain mismatches especially in the case of acquisitions or other corporate structuring changes.

--Kurt