Setup ssh Server on Unbuntu 20.10

1. Install openssh-server

    sudo apt update
    sudo apt install openssh-server
   

2. verify the service is up

    sudo systemctl status ssh
   
    [sudo] password for: 
    ● ssh.service - OpenBSD Secure Shell server
         Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
         Active: active (running) since Thu 2021-02-25 09:40:42 PST; 1h 19min ago
           Docs: man:sshd(8)
                 man:sshd_config(5)
       Main PID: 2890 (sshd)
          Tasks: 1 (limit: 9446)
         Memory: 1.3M
         CGroup: /system.slice/ssh.service
                 └─2890 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups
   
    Feb 25 09:40:42 ubuntu systemd[1]: Starting OpenBSD Secure Shell server...
    Feb 25 09:40:42 ubuntu sshd[2890]: Server listening on 0.0.0.0 port 22.
    Feb 25 09:40:42 ubuntu sshd[2890]: Server listening on :: port 22.
    Feb 25 09:40:42 ubuntu systemd[1]: Started OpenBSD Secure Shell server.
   
   

3. Turn on the firewall

    rongshen@ubuntu:/tmp/r0ngsh3n-vim$ sudo ufw allow ssh
    Rules updated
    Rules updated (v6)
   

4. Stop and restart the SSH server

   Stop

    sudo systemctl stop ssh
   

   Start

    sudo systemctl start ssh
   

   enable and disable

    sudo systemctl enable/disable ssh