How to Configure UBNT Wireless Devices to Use Licensed Frequency / Compliance Test

Like several previous release, Ubuntu Server 20.04 LTS doesn't give a password to root. This behavior from Ubuntu claimed to be more secure than have a password for root. But you can still doing ssh remote directly to your root Ubuntu Server even without a password by using RSA key pair without making change to this secure behavior.

In this post, I am using a newly installed Ubuntu Server 20.04 with OpenSSH server installed and without changing anything in sshd_config file. Some people will just gives a password to root and making a change in /etc/ssh/sshd_config to permit root login, etc.

Also we are not gonna using PuTTY, but native Windows 10 Command Prompt with OpenSSH client enabled. For you who didn't no about OpenSSH client in Command prompt yet, please read this previous post: Enable OpenSSH Client on Windows 10, PuTTY on Command Prompt.

How to remote SSH to Ubuntu Server 20.04 root Without Password Using Windows Command Prompt

• Open Windows Command Prompt
• Go to your user folder

cd %userprofile%

• Go to .ssh folder

cd .ssh

• Create RSA key pair using Command Prompt
  

ssh-keygen

Create RSA key pair using Command Prompt

• ssh-keygen will create 2 new files, use dir command to list files in the .ssh directory

  C:\Users\Andra\.ssh>dir
  Volume in drive C is Local
  Volume Serial Number is 50F0-0618
  
  Directory of C:\Users\Andra\.ssh
  
  25/06/2020  23:23    <DIR>          .
  25/06/2020  23:23    <DIR>          ..
  25/06/2020  23:23             1.679 id_rsa
  25/06/2020  23:23               411 id_rsa.pub
  25/06/2020  23:22               173 known_hosts
  3 File(s)          2.263 bytes
  2 Dir(s)  14.200.655.872 bytes free
  

• id_rsa is your private key and id_rsa.pub is your public key.
• Open id_rsa.pub with notepad, this command will do it

notepad id_rsa.pub

Open id_rsa.pub with notepad

• Copy all the content, and we will paste it later to Ubuntu Server
• Now, remote ssh to your Ubuntu Server using normal sudoers user and password

ssh user@ipaddress

• Edit or create authorized_keys file in root .ssh folder

sudo nano /root/.ssh/authorized_keys

• Copy the content of id_rsa.pub from notepad and paste it to ssh Command Prompt by right click on the terminal

• Open a new Command Prompt Window and remote ssh to the server root

ssh root@ipaddress

• If anything goes right, you'll log in to your Ubuntu Server 20.04 root without password

I am working on the video on How to remote SSH to Ubuntu Server 20.04 root Without Password Using Windows Command Prompt, it will be a short video. Keep alert by subscribing to my youtube channel https://www.youtube.com/channel/UC4SMlEsxgVhLs7BeKwjyq7g/