Set up SSH keys and disable password login Print

Logging in with an SSH key is much more secure than using a password and protects your VPS against brute-force attacks.

1. Create a key pair (on your computer)

1. Open a terminal or PowerShell and type ssh-keygen -t ed25519.
2. Confirm the location and optionally set a passphrase.

This creates a private key (id_ed25519, never share it) and a public key (id_ed25519.pub).

2. Copy the public key to the VPS

• macOS/Linux: ssh-copy-id root@YOUR-IP
• Windows PowerShell: type $env:USERPROFILE\.ssh\id_ed25519.pub | ssh root@YOUR-IP "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

Then test in a new window that ssh root@YOUR-IP works without a password prompt.

3. Disable password login

1. Open /etc/ssh/sshd_config (e.g. with nano).
2. Set PasswordAuthentication no and PermitRootLogin prohibit-password.
3. Check whether files in /etc/ssh/sshd_config.d/ override these values.
4. Test the configuration with sshd -t and restart the service: systemctl restart ssh (Debian/Ubuntu) or systemctl restart sshd (AlmaLinux/Rocky).

Important: Only close your current session once key login works in a second window. Keep a backup copy of your private key.