A mail account of a stupid user is set up to autorespond. The problem is that because of a horde of worm traffic and other spam which have false return addresses, these autorespond messages are often bounced back. However, these bounce messages are not going back to the original user. Instead they are bouncing back to some other system user. It seems the Return-Path: header is not being set correctly. I have googled about this a lot. Someone had suggested in a post that attempts by the autoresponder to set the envelope sender is failing because the user is not in exim's trusted_user setting. I currently have no clue which user to add in this setting. BTW, spamassassin is effective for this account. Could that be munging the envelope sender too? Anyone seen this happening? Any solutions?