Apparently due to changes at Spamhaus, the Fail2Ban on 42.2 (and earlier) no
longer function properly when using filter = postfix-rbl
In filter.d/postfix-rbl.conf the following line needs to be changed;
failregex = ^%(__prefix_line)sNOQUEUE: reject: RCPT from \S+\[<HOST>\]: 454
4\.7\.1 Service unavailable; Client host \[\S+\] blocked using .* from=<\S*>
to=<\S+> proto=ESMTP helo=<\S*>$
-=>
failregex = ^%(__prefix_line)sNOQUEUE: reject: RCPT from \S+\[<HOST>\]: 554
5\.7\.1 Service unavailable; Client host \[\S+\] blocked using .* from=<\S*>
to=<\S+> proto=ESMTP helo=<\S*>$
The return code has changed from 454 and 4.7.1 to 554 and 5.7.1 respectively.
The issue is present in the factory version as well.