Mikael Hansen wrote:

I have noticed if a@b is not a member of a list and c@d is, then
posting using From: a@b along with Reply-To: c@d works?

See the default setting for SENDER_HEADERS and the comments preceding it in Defaults.py. If you want to change it, change it in mm_cfg.py and restart mailman.

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