iptables
iptables is a user-space command-line utility for configuring the Linux kernel's netfilter firewall, which controls packet filtering, network address translation (NAT), and packet mangling. It allows administrators to define rules for incoming and outgoing network traffic, enabling security policies, traffic shaping, and network management. As a core component of Linux networking, it operates at the kernel level to enforce these rules efficiently.
Developers should learn iptables when working on Linux-based systems that require network security, such as servers, containers, or embedded devices, to implement firewalls, restrict access, and monitor traffic. It is essential for DevOps and system administrators to secure applications by blocking malicious IPs, setting up port forwarding, or creating DMZ configurations. Use cases include protecting web servers from DDoS attacks, configuring NAT for virtual machines, and managing traffic in cloud environments.