Definition
DNS, or Domain Name System, is the internet's phone book, translating human-readable domain names like www.example.com into machine-readable IP addresses such as 192.0.2.1. This distributed naming system makes navigating the internet possible by mapping names to numerical addresses. It is a fundamental component of network infrastructure, essential for almost all internet-based communication and services. For instance, when you type a website address into your browser, DNS is the system that finds the correct server to connect to. While often confused with the Uniform Resource Locator (URL) which specifies the exact location of a resource, DNS is the underlying mechanism that resolves the domain name part of the URL. Understanding DNS is crucial for IT professionals and appears on exams like CompTIA Security+, Network+, and CISSP.