安装

sudo yum install fail2ban
sudo apt-get
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install fail2ban 

服务状态

systemctl status fail2ban
systemctl restart fail2ban

查看敏感日志：

sudo tail -f /var/log/fail2ban.log

检查 fail2ban 状态

fail2ban-client status
fail2ban-client status sshd

解锁 ip

sudo fail2ban-client set sshd unbanip 192.168.1.8

问题记录

Failed during configuration: Have not found any log file for sshd jail #3567

From other point of view it is a configuration issue and can be surely simply fixed using:

- echo -e "[sshd]\nenabled=true" | sudo tee /etc/fail2ban/jail.local
+ echo -e "[sshd]\nbackend=systemd\nenabled=true" | sudo tee /etc/fail2ban/jail.local

With other words:

  $ sudo cat /etc/fail2ban/jail.local 
  [sshd]
+ backend=systemd
  enabled = true

References

• 如何使用 fail2ban 防御 SSH 服务器的暴力破解攻击
• https://github.com/fail2ban/fail2ban/issues/3292#issuecomment-1142503461
• https://github.com/fail2ban/fail2ban/issues/3567