dap1--- via Mailman-users writes:
I will PM the bounced email to you since there is too much sensitive information to sanitize it for this list.
That should be helpful. The important questions have to do with how mail is routed from you to the server, and then from the server to Yahoo!. Also, it would be nice to know what other recipient domains are experiencing the same "multiple address in From" phenomenon, and if they're seeing exactly the same thing.
Stephen: I am running a mailing list on my private Ubuntu server (this is a conversion for a defunct CentOS server) on my LAN. This is not for personal email but rather for a true mailing list. It is one list with a limited number of members. I am also running a web site for several different things.
We don't really need to know any of that. We're always interested in people's use cases of course, but that's random curiosity and "user stories" for Mailman marketing, not for support. The routing and the exact content of the full header (and sometimes message content) is crucial to issue diagnosis.
Steve
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan