Stanford uses ☞ Duo for the two-factor authentication. This is a mandatory requirement for everyone who wishes to connect with the Stanford computer environment. The setup is pretty simple, that is, you need to configure the auto-push (i.e., a mechanism that allows the app to push an authentication request to your default device). We strongly recommend your default device to be a smartphone or, alternatively, a tablet.
Follow the ☞ instructions given by the Stanford Security department to install Duo and enable the two-factor authentication.