[Mailman-Users] DMARC issues

[Stephen J. Turnbull]

Siniša Burina writes:

 > Basically, Yahoo insists that their own mail servers are the only
 > ones that can originate the message with @yahoo.com domain in the
 > From header. Not Return-Path, Not the envelope sender, but exactly
 > the From header in the message itself.  If this practice gets
 > adopted by more organizations, I don't know how else could this
 > problem be solved.

If yahoo wants to give their users an excuse to use a different
address and stop advertising yahoo, I have no problem with that. :-)

The straightforward thing for Mailman to do is to wrap mail from yahoo
addresses in a multipart/mixed with a text part explaining that Yahoo
is "knowingly interfering with" the mail service of their users, and
the mail itself in a message/rfc822 part.  As far as I know, no
component of DMARC allows digging into a message and trying to DMARC
the MIME parts.

Or just bounce them with a message stating that Yahoo no longer
permits its users to post to mailing lists, so please use a different
posting address.  I realize that most sites can't do that, but mine
can (and will if I get any complaints about this policy -- my
subscribers are sympathetic).

Steve