Stop Leaving Your Doors Open: 5 Essential Steps for Linux Server Hardening

Setting up a server is easy; keeping it secure is a different story. In an era where automated bots scan for vulnerabilities within seconds of a server going live, "default settings" are your biggest enemy. As a security enthusiast at NexxaCodeID, I’ve learned that security isn't just a feature—it’s the foundation. Here is how I implement Security by Design to harden Linux infrastructure against modern threats. ##SSH Hardening: The First Line of Defense Your SSH port is the primary target for brute-force attacks. Don't leave the keys under the mat. Disable Root Login: Never allow direct root access. Key-Based Auth: Disable password authentication entirely; use Ed25519 SSH keys. Change Default Port: Moving from port 22 to a custom port (e.g., 2204) cuts down 90% of bot noise. # Edit /etc/ssh/sshd_config Port 2204 PermitRootLogin no PasswordAuthentication no PubkeyAuthentication yes Implement a "Default Deny" Firewall The rule is simple: If it’s not required, it’s closed. Use UFW (Uncomp