ssh passwordless authentication with key file in linux

Step 1

Need to create a key file with following command

 ssh-keygen -t rsa -b 2048 -f ssh-key-name

then copy the file that you want to access it with this key

scp -r ssh-key-name.pub root@192.168.1.50

Step 2

In remote machine we need to add this key to authorized_keys with below command

cat ssh-key-name >> .ssh/authorized_keys

if authorized_keys file or .ssh is not available then we have to create it manually. 

goto the home directory of the user that you need to provide this access and create it.

mkdir .ssh

touch .ssh/authorized_keys 

chmod  700 .ssh

chmod 600 .ssh/authorized_keys

now add the key in authorized_keys

cat ssh-key-name > .ssh/authorized_keys

Step 3

Now we can access the remote server with following command

 ssh -i ssh-key-name root@192.168.1.50

it will login to the remote server without using password.