If you get this sudden error in the fail2ban.log

2015-04-20 11:13:17,722 fail2ban.jail   : INFO   Jail 'apache-honeypot' started
2015-04-20 11:13:17,739 fail2ban.actions.action: ERROR  iptables -N fail2ban-apache-honeypot
iptables -A fail2ban-apache-honeypot -j RETURN
iptables -I INPUT -p tcp -m multiport --dports apache-honeypot -j fail2ban-apache-honeypot returned 200

most likely you have spotted the character length limitation on the chain name.

I’ve discovered that the limit is 16 for the chain name length, but Fail2Ban prefixes it with the fail2ban- string which eats 9 precious characters, so only 7 remain.

To solve this issue you need to rename the iptables action to something like name=HONEY

$ cat /etc/fail2ban/jail.conf

[apache-honeypot]
enabled  = true
filter   = apache-honeypot
action   = iptables-allports[name=HONEY, protocol=all]
logpath  = /var/log/asterisk/full
maxretry = 3
bantime  = 600

That’s it! The issue is observed on Fail2Ban ver. 0.8 or older.