On 1/11/19 7:06 AM, David Gibbs via Mailman-Users wrote:

Does anyone know if there is a way to prevent MM from adding the original posters email address as a CC when the DMARC munging is done?

The following comment from Mailman/Handlers/CookHeaders.py describes the goals for handling the original From:

# MAS: We need to do some things with the original From: if we've munged
# it for DMARC mitigation.  We have goals for this process which are
# not completely compatible, so we do the best we can.  Our goals are:
# 1) as long as the list is not anonymous, the original From: address
#    should be obviously exposed, i.e. not just in a header that MUAs
#    don't display.
# 2) the original From: address should not be in a comment or display
#    name in the new From: because it is claimed that multiple domains
#    in any fields in From: are indicative of spamminess.  This means
#    it should be in Reply-To: or Cc:.
# 3) the behavior of an MUA doing a 'reply' or 'reply all' should be
#    consistent regardless of whether or not the From: is munged.
# Goal 3) implies sometimes the original From: should be in Reply-To:
# and sometimes in Cc:, and even so, this goal won't be achieved in
# all cases with all MUAs.  In cases of conflict, the above ordering of
# goals is priority order.

If your goal is to not expose the original From: address, you can make the list anonymous or if you have sufficient access, modify the code.

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