This plugin aids in rescuing genuine bounces.
Welcomelist bounce relays - welcomelist_bounce_relays
This is used to rescue legitimate bounce messages that were generated in response to mail you really did send. List the
MTA relays that your outbound mail is delivered through. If a bounce message is found, and it contains one of these
hostnames in a Received: header, it will not be marked as a blowback virus-bounce.
Default: empty