By using the ssh-keygen command, we can generate public and private key pairs, which can be used for password less SSH login to a server.
First you have to generate the keys from the server to which you need the password less login.
1. Login to the server
#ssh root@server
2. Generate the key
#ssh-keygen -t rsa
By default, the keys id_rsa (private key) and id_rsa.pub(public key) will be generated to the directory ~/.ssh
3. Move to the .ssh directory
#cd .ssh
4. Add the public key to SSH authorized_keys file
#cat id_rsa.pub >> authorized_keys
5. Modify the permission of authorized_keys file for privacy purposes
#chmod 600 authorized_keys
6. Delete the public key from the server
#rm id_rsa.pub
Now we have to configure the client side
1. Move to the .ssh directory
#cd .ssh
2. Copy the private key from the server to the client machine
#scp root@server:.ssh/id_rsa .
Once this is done, you will be able to login to the remote server via SSH without the password authentication from the client machine.
