Multi Factor Password Authentication

install with:

sudo apt install libpam-google-authenticator

configure with: (scan the barcode into your phone app while you are doing this)

google-authenticator

edit file:

sudo nano /etc/pam.d/sshd

add the following line to the bottom:

auth required pam_google_authenticator.so

edit the ssh server configuration

sudo nano /etc/ssh/sshd_config

change the line and make it look like this

ChallengeResponseAuthentication yes