Are you sure that he's receiving the list emails directly? Is it possible that he has a confederate or sympathizer on the list who is forwarding him the original list emails that he is then forging replies to?
I would double-check to make sure that even list members cannot see the addresses of other list members, because he may have gotten the email addresses that way. Your original idea of a 'red herring' message with a per-address uniquie identifier is theoretically sound, but it would have to be a message such that it would entice your abusive user to respond to it in order to find your 'leak'. The other responses have the best approach I think. If you don't have Terms of Service already that people had to agree to, then you need to retroactively come up with some, inform your users and require that they respond in the affirmative to the new rules or they're removed from the list. Then if the abuse continues, you definitely need to bite the bullet and move this towards legal action. I think this is especially true depending on what activities of the person lead you to categorize it as cyberstalking. ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://www.python.org/cgi-bin/faqw-mm.py Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/archive%40jab.org Security Policy: http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq01.027.htp