A Russian list member's account was closed. The member's address was
@mail.ru. That mail server is badly mis-configured. Not only does it send
the resulting bounce messages to the wrong address (the list posting
address!), but it put that member's e-mail address in the "From" field of
the bounce messages, making them valid as far as majordomo is
concerned. It was as if each bounce message was a reply to an individual
list message. This happened on a very active list.
Luckily I was watching when the first ones came through and removed
that address from the list immediately. It was too late by then to catch a
lot of them, since they were delayed about 24 hours and being spooled
somewhere. About two dozen of them actually went out over the list.
If this had happened when I was away from my computer for a couple of
days, it would have been a REAL mess because those bounce messages
themselves would have started bouncing too after about 24 hours, creating a
If you have any list members with addresses @mail.ru, beware.