ssh登录linux服务器的时候，经常会有提示

There were * failed login attempts since the last successful login.

说明有大量的非法登录尝试，有几种应对方法

1 换一个sshd端口

不过也经常会被扫到

2 禁止root账号直接ssh登录

修改/etc/ssh/sshd_config

PermitRootLogin no

修改之后重启sshd

systemctl restart sshd

3 使用fail2ban

安装

yum install fail2ban

修改配置

/etc/fail2ban/jail.conf，找到[sshd]，增加enable

[sshd]

# To use more aggressive sshd modes set filter parameter "mode" in jail.local:
# normal (default), ddos, extra or aggressive (combines all).
# See "tests/files/logs/sshd" or "filter.d/sshd.conf" for usage example and details.
#mode   = normal
filter = sshd
port    = ssh
logpath = %(sshd_log)s
backend = %(sshd_backend)s
enabled = true

启动

systemctl start fail2ban

配置开机启动

systemctl enable fail2ban

检查状态

fail2ban-client status sshd

对某个ip取消限制

fail2ban-client set sshd unbanip $ip