## Do not allow password-based SSH login \(keys only\)
First make sure you are actually logging in to the server using keys and not via a password, otherwise this will lock you out. Many hosting providers support uploading a public key and automatically set up key-based root login on new machines for you.
Edit `/etc/ssh/sshd_config` and find `PasswordAuthentication`. Make sure it’s uncommented and set to `no`. If you made any changes, restart sshd:
# Reject all other inbound - default deny unless explicitly allowed policy
-A INPUT -j REJECT
-A FORWARD -j REJECT
COMMIT
```
With iptables-persistent, that configuration will be loaded at boot time. But since we are not rebooting right now, we need to load it manually for the first time: