Linux Firewalls: How to Actually Secure a Cloud Server (iptables, nftables, firewalld, ufw)

A practical guide to the four major Linux firewall technologies - iptables, nftables, firewalld, and ufw. Covers real-world cloud server hardening with concrete examples, from locking down SSH to building zone-based configurations. Includes an honest comparison and an entirely unbiased opinion about which firewall is actually best.