https://linux.cn/article-5067-1.html
为了检验fail2ban状态（会显示出当前活动的监狱列表）：
~$ sudo fail2ban-client status
Status
|- Number of jail: 2
`- Jail list: ssh-iptables, sshd
可以检验一个特定监狱的状态（ssh-iptables 或者 sshd)
~ $ sudo fail2ban-client status ssh-iptables
Status for the jail: ssh-iptables
|- Filter
| |- Currently failed: 0
| |- Total failed: 18
| `- File list: /var/log/auth.log
`- Actions
|- Currently banned: 0
|- Total banned: 0
`- Banned IP list:
~ $ sudo fail2ban-client status sshd
Status for the jail: sshd
|- Filter
| |- Currently failed: 0
| |- Total failed: 18
| `- File list: /var/log/auth.log
`- Actions
|- Currently banned: 0
|- Total banned: 2
`- Banned IP list:
看到哪个状态下有需要被解禁的IP可以进行解禁，状态可根据上面检测出来的更换
~ $ sudo fail2ban-client set ssh-iptables unbanip ***.**.**.***
~ $ sudo fail2ban-client set sshd unbanip ***.**.**.***