Hi! 

> 
> The errors are probably from one of two sources:
(...)
> 2. Spammers trying to send to your list and getting rejected.

Unless I'm mistaken, rejected *senders* don't appear in the bounce messages, only presumed *subscribers*.

Since these messages appear randomly in time instead of immediately after a posting, and knowing that you have 300 bounces for 100 subscribers, I think that the problem is not related to the list itself. A spammer has probably put the address of your list, not in the "To:" field, but in the "From:" field; when rejected, the mail goes back to who the mail server thinks the originator is, that is, your list (your LISTSERV); thus the bounce messages. We had that problem with some of our lists here a while ago.

But the conclusion is the same: you have to ignore them.

Jean Bédard
Université Laval
Québec, Canada