Fail2ban vs SSH Keys: What Do You Really Need to Secure a VPS?
Security · · 8 min read
Any newly provisioned VPS server on Hetzner, DigitalOcean, or AWS receives thousands of automated connection attempts every day. When addressing server security, following a structured VPS hardening and security guide is fundamental to preventing unauthorized access.
In this article, we compare two core defensive mechanisms: exclusive cryptographic SSH key authentication and Fail2ban.
1. Cryptographic SSH keys: The first line of defense
Disabling password authentication (PasswordAuthentication no) and enforcing public/private key pairs completely eliminates traditional dictionary attacks.
- Advantages: Immune to password-guessing attempts (brute force).
- Limitations: Does not stop botnets from hitting port 22, creating massive log noise and consuming
sshdconnection resources.
2. Fail2ban: Active botnet blocking at the firewall
Fail2ban is a security daemon that continuously analyzes system logs (/var/log/auth.log or journalctl). When it detects repeated failed connection attempts from a single IP, it dynamically modifies the firewall (UFW / iptables) to block that IP for a defined period.
- Advantages: Drastically reduces log noise and frees up CPU/RAM resources.
- Limitations: If attacks come from distributed botnets (thousands of distinct IPs each making only 1 attempt), Fail2ban alone is less effective.
3. The recommended combination: Automated Hardening
The best practice in production is not choosing one over the other, but combining both:
- Enforce SSH Key-Only in
/etc/ssh/sshd_config. - Change the default SSH port (optional, but eliminates 95% of automated background scanning).
- Enable UFW allowing only strictly necessary ports.
- Configure Fail2ban to mitigate connection saturation.
With the Rust-based FerroSentry security agent in SecuryBlack, these points are audited every hour and you can apply SSH, UFW and fail2ban hardening from the panel, with confirmation.