Ubuntu 开启 SSH 服务

查看当前 Ubuntu 是否安装了 ssh-server 服务. 默认系统只安装了 ssh-client 服务.

使用 dpkg -l | grep ssh

$ dpkg -l | grep ssh
ii  libssh-4:amd64                             0.8.0~20170825.94fa1e38-1ubuntu0.2           amd64        tiny C SSH library (OpenSSL flavor)
ii  libssh-gcrypt-4:amd64                      0.8.0~20170825.94fa1e38-1ubuntu0.2           amd64        tiny C SSH library (gcrypt flavor)
ii  openssh-client                             1:7.6p1-4ubuntu0.3                           amd64        secure shell (SSH) client, for secure access to remote machines

安装 ssh-server 服务

sudo apt-get install openssh-server

查看安装情况

$ dpkg -l | grep ssh
ii  libssh-4:amd64                             0.8.0~20170825.94fa1e38-1ubuntu0.2           amd64        tiny C SSH library (OpenSSL flavor)
ii  libssh-gcrypt-4:amd64                      0.8.0~20170825.94fa1e38-1ubuntu0.2           amd64        tiny C SSH library (gcrypt flavor)
ii  openssh-client                             1:7.6p1-4ubuntu0.3                           amd64        secure shell (SSH) client, for secure access to remote machines
ii  openssh-server                             1:7.6p1-4ubuntu0.3                           amd64        secure shell (SSH) server, for secure access from remote machines
ii  openssh-sftp-server                        1:7.6p1-4ubuntu0.3                           amd64        secure shell (SSH) sftp server module, for SFTP access from remote machines
ii  ssh-import-id                              5.7-0ubuntu1.1                               all          securely retrieve an SSH public key and install it locally

查看启动状态, 使用 ps -e | grep ssh

$ ps -e | grep ssh
2081 ?        00:00:00 ssh-agent
25213 ?        00:00:00 ssh-agent
25514 ?        00:00:00 sshd

可以看到 sshd 服务已经启动.

如果没有则可以这样启动 sudo /etc/init.d/ssh start 或 sudo service ssh start

配置

ssh-server 配置文件位于 /etc/ssh/sshd_config，在这里可以定义 SSH 的服务端口，默认端口是22，可以自定义成其他端口，如222。

然后重启SSH服务：
sudo /etc/init.d/ssh stop

sudo /etc/init.d/ssh start

登录远程服务器

ssh username@ip