Ubuntu 20.04 - 安装、启用 OpenSSH 服务端

Ubuntu 系统信息：

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.3 LTS
Release:	20.04
Codename:	focal

安装 OpenSSH 服务端

在 Ubuntu 操作系统中，使用 sudo apt-get install openssh-server 安装 OpenSSH 服务端：

$ sudo apt-get install openssh-server

安装完成，使用 sudo systemctl status sshd 命令查看 OpenSSH 服务端的状态（第 1 行），可知 OpenSSH 服务端已经在运行（第 4 行）：

$ sudo systemctl status sshd
● ssh.service - OpenBSD Secure Shell server
     Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2022-02-21 09:09:50 CST; 50s ago
       Docs: man:sshd(8)
             man:sshd_config(5)
   Main PID: 4051 (sshd)
      Tasks: 1 (limit: 4588)
     Memory: 1.0M
     CGroup: /system.slice/ssh.service
             └─4051 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups

2月 21 09:09:50 mk-virtual-machine systemd[1]: Starting OpenBSD Secure Shell server...
2月 21 09:09:50 mk-virtual-machine sshd[4051]: Server listening on 0.0.0.0 port 22.
2月 21 09:09:50 mk-virtual-machine sshd[4051]: Server listening on :: port 22.
2月 21 09:09:50 mk-virtual-machine systemd[1]: Started OpenBSD Secure Shell server.

使用 SSH 客户端连接 SSH 服务端

在 Windows 10 操作系统中，打开 PowerShell，使用 ssh -l login_name destination 命令格式连接目标主机：

PS C:\Users\Admin> ssh -l mk 192.168.132.134
The authenticity of host '192.168.132.134 (192.168.132.134)' can't be established.
ECDSA key fingerprint is SHA256:U3XR4lbb5hhSp4fCycZwN/gO5thnzQ7K9EqcQ1HU5zM.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.132.134' (ECDSA) to the list of known hosts.
[email protected]'s password:
Welcome to Ubuntu 20.04.3 LTS (GNU/Linux 5.13.0-30-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

89 updates can be applied immediately.
1 of these updates is a standard security update.
To see these additional updates run: apt list --upgradable

Your Hardware Enablement Stack (HWE) is supported until April 2025.

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

登录成功，查看谁正在登录：

mk@mk-virtual-machine:~$ w
 11:28:20 up  2:32,  2 users,  load average: 0.00, 0.00, 0.00
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
mk       :0       :0               08:56   ?xdm?  44.74s  0.01s /usr/lib/gdm3/gdm-x-session --run-script env GNOME_SHEL
mk       pts/1    192.168.132.1    10:51    0.00s  0.03s  0.01s w

参考

如何在Ubuntu 20.04上启用SSH

SSH/OpenSSH/Configuring