Something I’ve been meaning to do for a while is look into the possibility of using 2 factor authentication, or 2FA, with SSH connections. This would add a much needed level of security to servers I host out in the wild. Here’s how I did it: The Google Authenticator mobile app used to be an open source project, it isn’t any more but the project has been kindly forked and looked after by Red Hat under the guise of the FreeOTP project.