Just the commands I always need to look up, because I forgot again...
- Overview over fail2ban status and jails
fail2ban-client status
- See which e.g. IPs are banned for sshd jail
fail2ban-client status sshd
- Unban an IP from sshd jail
fail2ban-client set sshd unbanip IPADDRESSHERE
- See which systems are actually banned
zgrep 'Ban' /var/log/fail2ban.log*