OpenSSH Passwordless Authentication

Method 1

1. Create a public and private RSA key pair.

   $ ssh-keygen -t rsa

   1. Follow the prompts to generate and save the RSA key.
2. Transfer the public key to the target host.

   $ ssh-copy-id <username>@<hostname>

   1. Follow the prompt to enter your password.
3. Test the passwordless authentication.

   $ ssh <username>@<hostname>

Method 2

1. Create a public and private RSA key pair.
   1. $ ssh-keygen -t rsa
2. Create the .ssh directory and set the permissions on the target host.
   1. Logon to the target host via ssh.
   2. $ mkdir .ssh
   3. $ chmod 700 .ssh
   4. $ touch .ssh/authorized_keys
   5. $ chmod 600 .ssh/authorized_keys
3. Transfer the public key to the target host.
   1. $ cat .ssh/id_rsa.pub | ssh <username>@<hostname> 'cat >> .ssh/authorized_keys'
   2. Follow the prompt to enter your password.
4. Test the passwordless authentication.
   1. $ ssh <username>@<hostname>