sophana wrote:
I think the problem was that when one ofthe recipients was unreachable, the mail went into defered state, to be retried later. The problem (bug?) is that the mail was sent again to all 50 recipients, explaining why so many users received lot of mails.
That looks like a problem on the *recipient* site. Normal processing of the mail should go ahead for all *reachable* adresses during the smtp dialogue, so the mail only gets deferred for the non-reachable recipients. On the other hand: If the recipient decides to *not* take the mail at all because one of the recipients is unreachable (or the limit of errors during the smtp handshake has been reached), you should never be able to reach the DATA phase in the smtp dialogue - so no mail gets sent at all.
If some mail gets sent, postfix *never* resends mails to those recipients who already got the mails.
But without seeing any logs everything's just a cloudy image in my crystal ball. It might also be that your setup is broken.
Ralph