1、在修改了sshd_config配置文件以后

vim /etc/ssh/sshd_config

2、重启ssh

service ssh restart

3、出现以下报错

Redirecting to /bin/systemctl restart ssh.service
Failed to restart ssh.service: Unit not found.

4、原因：以上命令都是centos6里面的命令，在centos7需要用

systemctl restart sshd

5、问题完美解决，nice