Passwordless SSH login

01. Check for existing SSH key pair

$ ls -al ~/.ssh/id_*.pub

If you see No such file or directory or no matches found it means that you do not have an SSH key and you can proceed with the next step and generate a new one.

02. Generate a new SSH key pair

$ ssh-keygen -t rsa -b 4096 -C "[email protected]"

Press Enter to accept the default file location and file name:

Output
Enter file in which to save the key (/home/yourusername/.ssh/id_rsa):

Next, the ssh-keygen tool will ask you to type a secure passphrase.

If you don’t want to use passphrase just press Enter

Output
Enter passphrase (empty for no passphrase):

To be sure that the SSH keys are generated you can list your new private and public keys with:

$ ls ~/.ssh/id_*

Output
/home/yourusername/.ssh/id_rsa /home/yourusername/.ssh/id_rsa.pub

03. Copy the public key

$ ssh-copy-id remote_username@server_ip_address -p server_port

You will be prompted to enter the remote_username password:

Output
remote_username@server_ip_address's password:

04. Login to your server using SSH keys

$ ssh remote_username@server_ip_address -p server_port

If everything went well, you will be logged in immediately.