Guide Explains Setting Up Iptables Firewall Policies on Linux Servers

A new DEV Community tutorial walks readers through configuring firewall policies with iptables, the packet-filtering utility built into Linux via the Netfilter framework. It explains the hierarchy of tables such as filter, NAT, raw, security, and mangle, along with the INPUT, OUTPUT, and FORWARD chains that govern traffic. The guide demonstrates practical rules for accepting loopback traffic, allowing established connections, opening specific ports like SSH, and forwarding traffic between network interfaces. It also covers NAT, logging, and saving rules so they persist across reboots.