[Mailman-Users] non-subscribers getting through--email address in "Real Name"

[Mark Sapiro]

On 07/19/2018 03:59 PM, Phil Stracchino wrote:
> 
> Actually, mailing lists and other redistribution are among the places
> DMARC notably breaks.  The real answer, which was created for this
> purpose, is ARC (Authenticated Received Chain).  That is designed from
> the start to pass through mailing lists unbroken.


Yes, ARC is designed for this and we are working on implementing ARC for
Mailman 3 but not 2.1.

ARC is a way that that I as an intermediary can say that I certify that
the message I received passed DMARC, but I transformed it in a way that
will cause DMARC to fail, but if my signature validates, downstream
should accept that DMARC passed.

The problem is downstream has to trust me. If I'm gmail.com, I'll
probably be trusted. If I'm msapiro.net, probably not. Python.org, who
knows.

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