Examine the headers of a bounced message closely.
"^Received: from.*for .*"
The regex above should tell you all the addresses the
mail went to or bounced from. (if the MTAs are nice)
Frank Bax wrote:
> Is there a way to include the original subscriber email address in any
> headers? We are getting several bounced messages for email addresses that
> are not in our mailing list. The only reason I can think of is that
> messages are being forwarded; and bounce message only tells me the
> forwarded address, not the original one.