5 steps to configure Password less SSH Login In Linux

Below are the steps to configure password less authentication between two hosts.

Consider you are on "machine1.company1.com" and you want to establish password less authentication on "machine2.company2.com" for user "user2"

Follow the below 5 steps:

1.       Log in to "machine1.company1.com" with user "user1".

Go to below directory:

cd /home/user1/.ssh/

2.       Generate public-private key pair using below command.

Note: If you already have the public and private keys in machine1 then step#2 can be skipped.

               ssh-keygen -t rsa

                Below are the details needs to give for the command

·         Enter file in which to save the key (/home/user1/.ssh/id_rsa):Press Enter (You can just press enter and accept the defaults if you have no requirement to change the directory)

·         Enter passphrase (empty for no passphrase): Press Enter

·         Enter same passphrase again: Press Enter

                Your identification (private key) has been saved in /home/user1/.ssh/id_rsa.

                Your public key has been saved in /home/user1/.ssh/id_rsa.pub.

                Verify the date of the above files.

3.       SSH to other machine2 and perform below steps.

·         ssh user2@machine2.company2.com , enter the password

·         cd /home/user2

·         Change .ssh directory to 700 permission (chmod 700 .ssh)

·         cd .ssh

·         Take the backup of authorized key file (authorized_keys authorized_keys_BKP)

·         Change authorized_keys to 600 permissions (chmod 600 authorized_keys)

4.       Execute the below command from machine1.info.company1.com" with user "user1":

                cat /home/user1/.ssh/id_rsa.pub | ssh user2@machine2.company2.com 'cat >> .ssh/authorized_keys'

5.       Close the current session and again log in to "machine1.company1.com" with user "user1"

                Try  ssh user2@machine2.company2.com

                This time it will not ask for the password.

                That’s all !!! You are done !!!

               

                Happy coding, Happy Learning J J