IMPORTANT

All the tutorials/steps provided here is only for educational purpose. Use/practise them wisely.

What is SSH Protocol#

• SSH (Secure SHELL) is an open-source and trusted network protocol that is used to log in to remote servers for the execution of commands and programs.

• It is also used to transfer files from one computer to another computer over the network using a secure copy (SCP) command and rsync command.

How to configure password less authentication#

IMPORTANT

This tutorial will walk you step by step through how to set up SSH passwordless login to a Linux server. Here, we have two servers. (server a and server b)

1. Now, Login to server a and generate a key pair.

ssh user@server-a
ssh-keygen -t rsa

2. When prompted, enter a filename and passphrase (if required).

3. Ensure the keys are generated at /home/cloud_user/.ssh/id_rsa.

• id_rsa contains the private key
• id_rsa.pub contains the public key

4. Now, login to server b and create SSH directory.

mkdir -p .ssh
ls -lla | grep ".ssh"

5. Upload the public key of server a to server b

ssh-copy-id user@server-b

6. Test the SSH Passwordless Login from server a to server b without password.

ssh user@server-b

Optional Steps: Additional Configurations and Troubleshooting#

1. Ensure the correct permissions are set on your .ssh directory and files:

• On server a

ssh user@server-a
chmod 700 ~/.ssh
chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub

• On server b

ssh user@server-b
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

Conclusion#

That’s it! You’ve successfully configured the passwordless authentication from your local machine to remote machines. If you have any doubts/issues/errors with the above contents, feel free to contact me. Cheers, Happy learning.