as root:

To check fail2ban status:

fail2ban-client status

To check fail2ban status of specific “jail” (sshd here):

fail2ban-client status sshd

To unban a specific IP (alternatively you can just wait 24 hours and they will automatically unban)

fail2ban-client set sshd unbanip 0.0.0.0

(insert IP address to unban instead of 0.0.0.0)