[Mailman-Users] from_is_list Wrap Message: what does that look like?

Mark Sapiro mark at msapiro.net
Wed Jan 11 14:09:47 EST 2017

On 01/11/2017 10:22 AM, Matt Morgan wrote:
> If I use from_is_list "Wrap Message," what will users see? The help page
> says "This is effectively a one message MIME format digest." Does that mean
> that the original message is going to show up as an attachment in some mail
> readers?


> What about in Digests? I have to imagine that wrapping is unnecessary on a
> digest, so the messages would just look like any other message. Is that
> accurate?

Yes. DMARC mitigations are not applied to messages in digests or archives.

> I'm trying to advise my list moderators on choosing between "Wrap Message"
> and "Reject." And considering whether to give them a choice. "Reject" is
> clear and understandable, but will annoy some of our users, none
> (approximately) of whom will understand at first why we're doing it. But
> "Wrap Message" may confuse everybody else, if those messages look funny or
> take an extra step to read.

Yes, that's the dilemma. Note that from_is_list does not have a 'reject'
option. That applies only to dmarc_moderation_action, and setting it to
'reject' is only appropriate in limited situations when it is possible
and appropriate to force list members to not post from Yahoo, AOL or
other domains that publish DMARC p=reject or p=quarantine. You are
basically punishing users based on the policy of their ESPs which they
can control only by switching providers. For some lists in some
situations, this can be appropriate, but in general, it is not. And your
users won't understand and if they complain to Yahoo, AOL, etc., they
will be lied to and told the list is the problem.

For most lists, dmarc_moderation_action = Munge From turns out to be the
best (or least harmful/disruptive) choice. Munge From does not change
the MIME structure and with compliant mail readers at least does not
change the results of 'reply', 'reply all' and 'reply list'.

The big negative of Munge From is the message's From: header no longer
contains the address of the author of the message so the message is no
longer strictly compliant with RFCs 822, 2822 and 5322.

> Anybody who has experience with how list subscribers respond to these
> changes, please let me know!

List subscribers with iThings do not like Wrap Message. At least some
other mobile clients also have issues with this format. As I said, Munge
From, despite it's non-compliance, is usually the better option.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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