Comment # 3 on bug 1036928 from Miuku .

I can confirm that the updated RegExp line from Github does indeed work
properly:

==> mail <==
2017-04-30T15:00:35.792861+03:00 ext-gw postfix/smtpd[1159]: NOQUEUE: reject:
RCPT from unknown[14.230.81.243]: 554 5.7.1 Service unavailable; Client host
[14.230.81.243] blocked using zen.spamhaus.org;
https://www.spamhaus.org/query/ip/14.230.81.243; from=<xxxREMOVEDxxx>
to=<xxxREMOVEDxxx> proto=ESMTP helo=<static.vnpt.vn>

==> fail2ban.log <==
2017-04-30 15:00:36,504 fail2ban.actions        [32042]: NOTICE  [postfix-rbl]
Ban 14.230.81.243