sudo -i
echo "root:xuezhangnet.net.852" | sudo chpasswd root
sudo sed -i 's/^#\?PermitRootLogin.*/PermitRootLogin yes/g' /etc/ssh/sshd_config
sudo sed -i 's/^#\?PasswordAuthentication.*/PasswordAuthentication yes/g' /etc/ssh/sshd_config
sudo reboot
xuezhangnet.net.852 修改为你自己设置的 root 密码。若不修改,默认密码为 xuezhangnet.net.852