Step 4: Securing OpenSSH
The OpenSSH server configuration should be located at /etc/ssh/sshd_config but we aren't going to edit this file. We are going to create a new file at /etc/ssh/sshd_config.d/hardening.conf. (add video)
X11Forwarding no
PermitEmptyPasswords no
MaxAuthTries 3
# NOTE: this will disable password authentication entirely! Setup SSH keys before applying this config!
PubkeyAuthentication yes
PasswordAuthentication no
PermitRootLogin no
Protocol 2