### 
```sh
sudo nano /etc/ssh/sshd_config
#找到并修改以下行：
PermitRootLogin prohibit-password
#改为：
PermitRootLogin yes
# 此外，确保以下行存在并且未被注释：
PasswordAuthentication yes
# 重启SSH服务：
sudo systemctl restart sshd
# 为root用户设置密码：
sudo passwd root 
 

ssh-copy-id -i ~/.ssh/id_rsa.pub  root@43.154.208.215
ssh-copy-id -i ~/.ssh/id_rsa.pub  root@192.168.1.34
ssh-copy-id -i ~/.ssh/id_rsa.pub  root@192.168.1.23
ssh-copy-id -i ~/.ssh/id_rsa.pub  root@1.15.21.245

```