SSH設定與連線

1. sshd 允許 root 登入的參數 PermitRootLogin 設定：
   1. yes：允許
   2. no：不允許
   3. prohibit-password (without-password)：不允許以輸入密碼的方式登入
   4. forced-commands-only：只允許在登入命令用公鑰授權登入。
2. PermitRootLogin 預設是 prohibit-password，修改成 yes。

   [root@999999 ~]# vim /etc/ssh/sshd_config
   [root@999999 ~]# grep PermitRoot /etc/ssh/sshd_config
   #PermitRootLogin prohibit-password
   PermitRootLogin yes
   # the setting of "PermitRootLogin without-password".
   

3. 重新啟動 sshd 服務。

   [root@999999 ~]# systemctl restart sshd.service
   

4. 從 host 主機以 ssh 登入 kvm8。

   [dywang@deyu ~]$ ssh root@kvm8.deyu.wang
   The authenticity of host 'kvm8.deyu.wang (192.168.122.8)' can't be established.
   ECDSA key fingerprint is SHA256:WaRiVLOS0JYkmNagaoEUu3MoCDEzqxougcjB0uJ99QQ.
   Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
   Warning: Permanently added 'kvm8.deyu.wang' (ECDSA) to the list of known hosts.
   root@kvm8.deyu.wang's password:
   Last login: Mon Aug 29 15:35:12 2022 from 192.168.122.1