How to Set Up SSH with Google Authenticator Two-Factor

Step 1: Run this command belowing
# yum install -y google-authenticator
If it not found, please run this yum install -y epel-release then run again above command.

Step 2: Press command line google-authenticator and confirm yes or y.

Step 3: Edit file /etc/pam.d/sshd
Add: auth required pam_google_authenticator.so
Comment: #auth       substack     password-auth # To prevent ssh by password, obligate ssh by key.

Step 4: Edit file /etc/ssh/sshd_config
Change ChallengeResponseAuthentication no to ChallengeResponseAuthentication yes
AuthenticationMethods publickey,keyboard-interactive
Step 5: Restart SSH and join download app Google Authenticator
Android: https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2&hl=vi
IOS: https://apps.apple.com/us/app/google-authenticator/id388497605

Step 6: Finally and SSH with code Google Authenticator