Diagnosing_issues_with_fail2ban - Creative Computing Wiki

to list blocked IP's

iptables -L

To unblock an ip:

(pre 8.8) fail2ban-client get ssh actionunban 10.xx.15x.12x
(post 8.8) fail2ban-client set ssh unbanip 10.xx.15x.12x

where ssh is the jail name and 10.xx.15x.12x is the ip that has been banned.