whitelist_bounce_relays hostname [hostname2 ...]
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
The hostnames can be file-glob-style patterns, so relay*.isp.com will work.
Specifically, * and ? are allowed, but all other metacharacters are not.
Regular expressions are not used for security reasons.
Multiple addresses per line, separated by spaces, is OK. Multiple
whitelist_bounce_relays lines are also OK.