Re: DMARC methods in mailman

Philip Homburg <> Wed, 21 December 2016 12:11 UTC

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Subject: Re: DMARC methods in mailman
From: Philip Homburg <>
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In-reply-to: Your message of "Wed, 21 Dec 2016 02:57:17 -0800 ." <>
Date: Wed, 21 Dec 2016 13:10:16 +0100
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Cc: S Moonesamy <>
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>>What about adding a checkbox in the mailman profile for subscribers of the
>>lists that basically says: if you detect that the sender is using DMARC then
>>please rewrite the From header.
>There is already code in Mailman, e.g. if not 
>(msgdata.get('from_is_list') ... to do the above.  The configuration 
>can be set by AMS.

Just to be clear, is this an option that individual subscribers of the mailing
list can set?

For me, the current IETF lists work fine. My MTA completely ignores DMARC,
so it would be nice not to be subjected to mangled From headers.

>>People who receive the list on a yahoo account would have to mark the checkbox
>>(though maybe a list of default domains can be hacked in such that new
>>subscribers for those domain would get it set automatically)
>The focus has been on Yahoo because of a message which was posted 
>several years ago.  I collected some statistics for an IETF mailing 
>list.  Approximately 40% of the subscribers are using [1] DMARC; most 
>of then are not using Yahoo.

Are you talking about senders or recipients? The reason yahoo stands out is
because yahoo seems to be one of the few providers that rejects or bounces
mail that fails DMARC checks.

Or are you saying that at the moment 40% of the subscribers of IETF lists reject
or otherwise not receive mail from DMARC protected senders?