The Production Server Hardening Checklist: Protecting Linux VPS from Attacks

Every server connected to public internet infrastructure is subject to thousands of automated dictionary attacks, port scans, and exploit attempts every single day. Default VPS configurations leave critical entry points wide open.

Essential SSH and Access Hardening

Never allow password-based authentication on production systems:

• Disable root login over SSH (`PermitRootLogin no`) and mandate strong Ed25519 cryptographic SSH keypairs.
• Move SSH off standard port 22 to eliminate 95% of automated script-kiddie brute-force logs.
• Implement Fail2ban with aggressive IP jail rules banning repeat authentication failure IPs for 24 hours.

Strict UFW Firewall Rules and Reverse Proxies

Only expose ports that genuinely serve public traffic:

1. UFW default-deny incoming policy: Explicitly opening only Port 80, Port 443, and the customized SSH port.
2. Isolating database ports (PostgreSQL 5432, Redis 6379) strictly to internal Docker networks or private VPC subnets.
3. Routing all inbound traffic through Cloudflare or reverse proxies to filter Layer 7 DDoS attacks before reaching your host.

Server security is not a single tool; it is a layered defense-in-depth model that makes penetration too expensive and time-consuming for attackers.

Harden Your Production Infrastructure

Ensure your production servers withstand targeted attacks with deep OS-level hardening and automated liveness alerting.