Summary  
This chapter covers client–server communication and DNS resolution, explaining how a client sends a network request through an ISP, how DNS maps a domain name to an IP address, and how the server returns resources for rendering.  

General domain of usage  
Web browsing

The Internet is a vast network that connects devices worldwide. We will explore the fundamental concepts behind its functioning by focusing on three key terms:
- **Client**: a device or application that initiates a request for services or data from a server over the Internet;
- **Internet Service Provider (ISP)**: a company that provides access to the Internet and related services;
- **Domain Name System (DNS)**: a system that translates human-readable domain names into numerical IP addresses that computers use to identify each other on the network.

## What Happens When You Open a Website?

Let's use `www.google.com` as an example:
1. **Client → ISP**: your browser sends a request to your Internet Service Provider. The ISP acts as your entry point to the Internet;
2. **DNS lookup**: the ISP forwards your request to a DNS server.
DNS converts the domain name (`www.google.com`) into the IP address of the Google web server;
3. **Connecting to the server**: once the IP address is known, your browser can contact the correct web server directly;
4. **Receiving data**: the server sends back the required files (HTML, CSS, JavaScript, images, etc.);
5. **Rendering the webpage**: your browser processes these files and displays the final webpage.

Although the Internet infrastructure is complex, accessing a website essentially comes down to one key step: **finding the correct IP address through DNS**.

Once that happens, the client and server can communicate normally.

Note

What role does the DNS server play in accessing a specific website?

Learn the essentials of HTML, the backbone of every website. Structure content with tags and attributes, build clear document layouts, and add images, links, and tables. Create accessible, user-friendly forms for capturing input and interaction. Practice crafting well-structured, functional web pages while following best practices. Start your web development journey by mastering HTML.

Explore the inner workings of the web. Learn how data travels across networks, discover the role of protocols, and unravel the mysteries of IP addresses and domain names. Gain a high-level understanding of how web browsers and servers communicate to deliver web content.

Discover the power of tags to structure content, from headings and paragraphs to lists and tables. Learn how to enhance the elements with attributes.

The core of HTML document structure. Learn the components of an HTML document, including the doctype declaration, head, and body. Understand the purpose of each element and how they contribute to the overall structure of a webpage.

Make a web page more appealing with the help of media such as images, audio, and video. Work with structured tabular data in the form of tables.

Explore the versatility of HTML forms. Learn to design intuitive and user-friendly forms by leveraging key concepts and techniques. Discover how forms enable user interaction and data submission on websites. 

How Does the Internet Work?

What Happens When You Open a Website?