通过CRT远程登录Ubuntu时遇到报错：
The client has disconnected from the server. Reason:
Unable to authenticate using any of the configured authentication methods.
Ubuntu初始登录只能是普通用户，想用root登录，需普通用户登录，然后切换为root用户，先设置root密码，再更改sshd_config文件
ixo@snort:~$ sudo su
Password:
root@snort:/home/ixo#sudo passwd root
New password:
Retype new password:
passwd: password updated successfully
root@snort:/home/ivo# nano /etc/ssh/sshd_config
注意：是sshd_config，而不是ssh_config
...
#port 22
port 22
#PermitRootLogin prohibit-password
PermitRootLogin yes # 允许root直接登录
...
保存后重启ssh服务
