How to Set Up SSH Key Authentication

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SSH keys are safer than passwords and make logins passwordless. Here’s how to set them up and disable password auth.

Step 1: Generate a key pair (on your computer)

ssh-keygen -t ed25519 -C "you@example.com"

This creates ~/.ssh/id_ed25519 (private) and id_ed25519.pub (public). Never share the private key.

Step 2: Copy the public key to the VPS

ssh-copy-id root@your-vps-ip

Step 3: Test and harden

Log in with the key, then disable password login in /etc/ssh/sshd_config:

PasswordAuthentication no
PermitRootLogin prohibit-password

Reload with:

sudo systemctl reload ssh

Before you close the session, open a second terminal and confirm key login works — locking yourself out is the classic mistake.

Keep a backup of your private key, and consider an SSH config alias for quick access. This works on any VPS with full root; RackNerd’s 1 GB plan at $21.99/yr is a fine place to start.