Date: 2018jun19 OS: Linux Q. fail2ban before 0.8.8 temporarily unban an address A. First list all iptables rules. Chains starting with "fail2ban-" are for fail2ban.

iptables -L -n

Or try without the -n to see names (which can add some info)

iptables -L

Note the chain name (case sensitive, based on your jail names) and IP-address. Then do:

iptables -D <chain> -s <ip-address> -j DROP

For example

iptables -D fail2ban-ProFTPD -s 1.2.3.4 -j DROP

fail2ban after 0.8.8 has an option with the fail2ban-client command

fail2ban-client set <jail> unbanip <ip-address>