1.重装ssh服务

sudo apt remove --purge openssh-server

sudo apt install openssh-server

2.修改配置(默认情况下是不开启端口的)

sudo nano /etc/ssh/sshd_config

Port 22 # 把这一行前面的#去掉
PasswordAuthentication yes # 改成yes

3.重启服务

sudo service ssh restart