[Mailman-Users] (relatively) new DMARC issues - and Gmail

Richard Damon Richard at Damon-Family.org
Sat Mar 31 20:32:42 EDT 2018

On 3/31/18 6:55 PM, Lindsay Haisley wrote:
> On Sat, 2018-03-31 at 17:33 -0500, Lindsay Haisley wrote:
>> I've had to deal with Gmail's honey-potting before, and I can do it
>> again if necessary. I don't imagine that you've ever done commercial
>> email administration, Richard, or you might have something constructive
>> to say instead of just spewing admonitions to "do better".
> And in any event, my original post was a FYI, mainly concerned with the
> interaction between Google's Gmail policies and _any_ system which
> munges headers to deal with DMARC, as MM does - combined with the fact
> that a lot of spammers these days seem to be sending mail over From
> addresses which publish a DMARC p=reject policy. This is a particular
> nasty combination which can effectively neutralize Gmail's spam
> blocking.
> I'm not looking for advice from anyone on how to run FMP's mail system,
> nor for admonitions to do a better job of spam blocking, so if that's
> what you want to say, please email me personally because it's OT for
> this list.
> If anyone has insights into this issue that _don't_ relate to FMP's
> email service, or which constitute constructive insights based on
> knowledge and experience, I'd love to hear them. Otherwise, please just
> leave it!
I see the issue as largely not as big of an issue for most mailing list 
than a more generic mail forwarding system. I suspect most mailing lists 
are setup for only subscribers posting, which cuts out a lot of the spam 
issues, and many of those also it is preferred to reply to list instead 
of poster so the munged from isn't as important.

I suspect the major use of non-subscriber lists would be support lists 
where the subscribers are the support team, so more able to handle the 
technical challenges of dealing with the spam issues.

For a mailing list, because reply-all is more often used, it make 
differentiated munged From's (if needed), you likely want to plus-hack 
the From line (listname+sender at listdomain), though that might also 
create duplicate posts.

Richard Damon

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