[Discuss] DMARC issue, Yahoo and beyond

[blu at nedharvey.com (Edward Ned Harvey (blu))]

> From: John Abreau [mailto:abreauj at gmail.com]
> 
> We don't, yet. We don't want to make any hasty changes that could break
> the list.
> 
> Jerry will be running some tests on a couple of low-traffic lists to evaluate the
> risks, before we do anything to high-volume lists such as this one.

I think you mean to say, nothing special is done.  Which means, if anybody posts to the list from a yahoo address (or any domain where dmarc is set to reject or quarantine) then any recipients on google, microsoft, or other domains where sender dmarc policy is honored, will bounce.  And the end result is, anybody sends from Yahoo will result in *other* people getting unsubscribed from the list because their mail bounces.

The official mailman suggestion, created specifically for this purpose, is to set from_is_list = no, and set dmark_moderation_action = munge.

This way, all the users currently using the list experience no change.  You and I post to the list, and it goes through same as always.

But somebody posts to the list from a domain where dmarc policy is reject or quarantine, their from address will be munged, so it's safe for everyone else to receive it.