安装
yum -y install epel-release
yum -y install fail2ban
配置
新建文件：/etc/fail2ban/jail.local，输入内容如下：
[DEFAULT]
# 白名单
ignoreip = 127.0.0.1/8
# 1年
bantime = 1y
# 5分钟内失败5次，就被禁ip
findtime = 5m
maxretry = 5
[sshd]
enabled = true
filter = sshd
port = 22
logpath = /var/log/secure
启动fail2ban
systemctl restart fail2ban.service
systemctl enable fail2ban
# 验证启动成功，不出现Error说明成功
fail2ban-client status sshd
常用命令
# 查看被ban IP，其中sshd为名称，比如上面的[sshd]
fail2ban-client status sshd
# 删除被ban IP
fail2ban-client set sshd delignoreip 192.168.111.111
# 如果上述命令出错，可尝试执行
fail2ban-client set sshd unbanip 192.168.111.111
# 查看日志
tail /var/log/fail2ban.log