How to Harden Your VPS With Firewall, SSH Config, and Fail2ban

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Public servers face automated attacks within minutes of going online, including password brute-force attempts, port scans, and exploit probes. AhnLab's Q1 2025 report found that two malware families, P2PInfect and Tsunami, together made up around 80% of samples collected from compromised Linux SSH servers. A VPS typically sits behind two distinct firewalls: a provider-level network firewall managed via the hosting control panel, and a host-level firewall such as UFW or firewalld running inside the operating system itself. Security best practice recommends running both layers simultaneously, as each covers gaps the other cannot, rather than treating them as interchangeable. A default-deny firewall policy, hardened SSH settings, and Fail2ban together form a three-layer defence that can be configured in under an hour.

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ProgrammingDEV Community ·

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