# workaround not recognized commands, possibly caused by some firewalls
/^500 unrecogni[zs]ed command/ 400 Message not accepted by Exim. Retrying later
/^500 5\.3\.3 Unrecogni[zs]ed command/ 400 4.3.3 Message not accepted by Exchange. Retrying later
/^502 5\.5\.2 Error: command not recognized/ 402 5.5.2 Message not accepted by Postfix. Retrying later
/^500 Syntax error/ 400 Message not accepted by Lotus. Retrying later

# Do not bounce the spam from remote server
/^55[04] 5\.7\.1 Message .* Content / 440 4.7.1 Message rejected as spam

# Do not bounce custom 5xx codes
/^5[0-9][0-9] \D+/ 400 4.0.0 Message rejected with 5xx error code
/5\.7\.1 .* Spam collector pollution attempts are forbidden/ 440 4.7.1 Message rejected from another Scrollout Collector