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Re: [dmarc-ietf] Ratchets - Disallow PCT 1-99

John Levine <johnl@taugh.com> Wed, 21 July 2021 17:19 UTC

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Date: Wed, 21 Jul 2021 13:19:28 -0400
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From: John Levine <johnl@taugh.com>
To: dmarc@ietf.org
Cc: laura@wordtothewise.com
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Subject: Re: [dmarc-ietf] Ratchets - Disallow PCT 1-99
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It appears that Laura Atkins  <laura@wordtothewise.com> said:
>-=-=-=-=-=-
>
>This is going to cause difficulties in deployment for a lot of companies and domains. Experience tells us that p=quarantine pct=0 detects forwarders
>and other types systems that modify and break DMARC authentication. These systems are undetectable when p=none is in place. 

I can see how that would be useful to help debug your mailing list software but it's not so clear
how you use it as a sender.

Is the idea that you see a bunch of fails in the report that look like lists, then turn on pct=0
and see if they go away?

I suppose we could leave pct=0 as a hint to forwarders to turn on their DMARC evasion hacks.

R's,
John

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