Key Based / Passwordless SSH Authentication on Linux Servers
Password Less authentication to Linux servers makes the system admin's life easy. To Implement password less or Keys based authentication we have to generate Public and Private keys , Copy the Pubic keys to remote Linux servers either manually or by ssh-copy-id command .
In My scenario I have Ubuntu laptop and daily I have to login to lot of remote Linux servers , Follow the below steps to achieve password less / Keys based authentication :
Step:1 Generate Public and Private keys , using below command
# ssh-keygen -t rsa
Above command will save the keys under ~/.ssh directory with the name id_rsa & id_rsa.pub. Leave the passpharse empty while executing above command.
Step:2 Copy the public key to remote linux servers
# ssh-copy-id -i /root/.ssh/id_rsa.pub firstname.lastname@example.org
ssh-copy-id command will automatically copy the contents of id_rsa.pub file to ~/.ssh/authorized_keys file of remote linux server
Note : if we don't want to use ssh-copy-id command , then manually Append contents of file "id_rsa.pub" to "~/.ssh/authorized_keys" remote linux server and change the permissions of "~/.ssh/authorized_keys" to 755.
Example:3 Now access the remote linux server and it will not ask for the password.