How to Set Up SSH Two Factor Authentication on Ubuntu 18.04, 18.10 Server

This tutorial will show you how to set up SSH two factor authentication on Ubuntu 18.04/18.10 server using the well-known Google Authenticator. It will greatly increase the security of your OpenSSH server.

How Two Factor Authentication Works

Normally, you only need to enter a password or use SSH key to log in to your Ubuntu server remotely. Two factor authentication (2FA) requires you to enter two pieces of information in order to login. So you will also need to enter a one-time password generated by Google Authenticator to log in to your SSH server. These days many websites and services (Facebook, Google, Twitter, etc) offer 2FA for users to secure their accounts and it’s a good idea to also enable 2FA on your SSH server.

Read full tutorial here: https://www.linuxbabe.com/ubuntu/two-factor-authentication-ssh-key-ubuntu-18-04