If you’re a Linux administrator and looking to lock down your Linux servers and desktops as tight as possible, you owe it to yourself to make use of two-factor authentication. This should be considered as “no-brainer” as they come. Why? Because by adding two-factor authentication, it becomes exponentially more difficult for malicious users to gain access to your machines. With Linux, it is possible to set up a machine so that you cannot log into the console or desktop or by way of secure shell, without having the two-factor authentication code associated with that machine.
I’m going to walk you through the process of setting this up on Ubuntu Server 16.04. If you’ve attempted this process before, know that the steps have changed and the previously detailed method no longer works.
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