[Mailman-Users] Mailman & DMARC policy = none?

[Richard Damon]

On 12/31/18 3:08 PM, Mark Sapiro wrote:
> On 12/31/18 10:36 AM, David Gibbs via Mailman-Users wrote:
>> I'm curious as to how people are setting
>> 'dmarc_none_moderation_action'... which controls how Mailman handles
>> domains with a dmarc policy action of none (like gmail.com).
>>
>> Is there a compelling reason to set it to Yes so that messages from such
>> domains are munged or wrapped?
>
> No. There is no compelling reason to set it to Yes. It does not affect
> mail delivery. It only affects the reports sent by list recipient's
> service providers to the original From: domain which publishes p=none.
> Read the entire thread at
> <https://bugs.launchpad.net/mailman/+bug/1539384>. The originator of
> that bug report would like every Mailman list to apply
> dmarc_moderation_action unconditionally to posts From: domains that
> publish any DMARC policy including p=none.
>
> Implementing this as a list option does not satisfy the originator
> because he is concerned about mail From: his own domain which publishes
> p=none to lists operated by others which he does not control.
>
> It would have been better if this feature had never been implemented,
> and it is not in Mailman 3.
>
I would say that the 'backscatter' in the report is actual real
information telling the postmaster for the domain that their current
policies do not align with a a DMARC policy of reject (or maybe even
quarantine) as they are allowing there users to use RFC compliant
re-mailing systems (aka mailing lists) that don't naturally meet the
requirements of the (in my opinion poorly designed) DMARC system.

-- 
Richard Damon