Common Firewall Terminology

Navigating the world of firewall configuration requires familiarity with specific terminology. Understanding these terms ensures effective communication with security professionals and accurate implementation of security policies.

Rules and Policies: Firewall rules define specific actions for network traffic matching certain criteria. A policy is a collection of rules that implement your security strategy. Rules typically specify source/destination addresses, ports, protocols, and actions (allow, deny, log).

Zones: Security zones represent network segments with different trust levels. Common zones include "trusted" (internal network), "untrusted" (internet), and "DMZ" (demilitarized zone for web servers). Traffic between zones is controlled by inter-zone policies.

NAT (Network Address Translation): This technique modifies IP addresses in packet headers, often used to hide internal server addresses from external networks. NAT can provide an additional security layer by obscuring your internal network structure.

Default Deny: A fundamental security principle where all traffic is blocked by default, and only explicitly allowed connections are permitted. This approach ensures that any oversight in rule configuration errs on the side of security rather than accessibility.