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Re: [dmarc-ietf] Signaling forwarders, not just MLMs

John R Levine <johnl@taugh.com> Thu, 13 April 2023 16:01 UTC

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Date: Thu, 13 Apr 2023 12:01:40 -0400
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From: John R Levine <johnl@taugh.com>
To: Barry Leiba <barryleiba@computer.org>
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Subject: Re: [dmarc-ietf] Signaling forwarders, not just MLMs
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>> Anyone who does forwarding is damaged by DMARC because there are a lot of
>> people who do DMARC on the cheap with SPF only.
>
> This brings up another issue, I think: that there should also be
> stronger advice that using DKIM is critical to DMARC reliability, and
> using SPF only, without DKIM, is strongly NOT RECOMMENDED.

Well, it depends whether you care whather people get your mail.

I'm trying to figure out where best to say this, but when you say 
p=reject, you are saying your mail is *not* important, and if there is any 
doubt about it, you want recipients to throw it away, even though some of 
your real mail will get lost.

In ADSP I made the equivalent policy "discardable" to reinforce this 
point.  My co-authors weren't happy about it, but they couldn't disagree.

R's,
John

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