OpenSSH Passwordless Authentication

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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>