> > smtp_bind_address is a new feature as of 2.7, clearly stated at the top
No, smtp_bind_address is available in all Postfix versions since 2001. If Postfix complains like this: postfix/master[5309]: /etc/postfix/master.cf: line 6: bad transport type: smtp_bind_address=174.121.222.21 then line 6 in master.cf starts with "-o smtp_bind_address=174.121.222.21" without the leading whitespace. No amount of Postfix reinstalling will fix that problem. Wietse