Module 3:
Domains, DNS, and Hosting

Module 3 explains how domain names, DNS, hosting, and CDNs work together to make websites reachable on the Internet. It begins by showing that domain names are human-readable names that point people toward online services, while DNS is the system that translates those names into the technical information computers need. The module then explains how DNS lookup works, including resolvers, root servers, top-level domain servers, authoritative name servers, caching, and DNS records such as A, AAAA, CNAME, MX, TXT, and NS records.

The module also explains web hosting and web servers, showing that DNS helps users find a site, but hosting is where the website actually lives and responds to requests. It compares different types of hosting, including shared hosting, VPS, dedicated hosting, cloud hosting, serverless hosting, managed hosting, and static site hosting, and then explains how content delivery networks (CDNs) improve speed, reliability, and sometimes security by serving content from locations closer to users. Overall, the module gives a foundational picture of how websites are named, located, stored, delivered, and protected across the modern Internet.