General Information

SSH key based authentication (password-less).

The following virtual machines will be used:

• server1.example.com (192.168.1.150) → The SSH client
• server2.example.com (192.168.1.151) → The SSH server

Key based authentication involves a private and public key.
The private key stays on the source system, the public key is distributed to all remote systems.

Generate the private/public key pair.

ssh-keygen

• RSA is the default key type
• Prompted for file to save private key (~/.ssh/id_rsa)
• Prompted for file to save public key (~/.ssh/id_rsa.pub)

Copy the public key to a remote system

ssh-copy-id myserver

• Prompted for password login
• Next normal ssh login will be password-less

Key Pair with Passphrase

If you created the key pair with a passphrase, it is useful to cache the passphrase for a bash session to avoid re-entering it for each ssh connect.

Start the ssh-agent for the current shell

ssh-agent bash

Add the passphrase

ssh-add

• Prompted for the ssh key passphrase

Connect as normal with ssh, you should not be prompted for a password if the public key has already been copied to the remote server.