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How Does the Internet Work? A Step-By-Step Guide

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The internet. We use it every day, whether knowingly or unknowingly. Many depend on it for work and survival. Without the internet, life as we know it will cease to exist.

But what is the internet? How does it work? Let’s take a quick overview of its history to understand how it works and then follow the journey of a piece of data as it travels around the world on the global network that is the internet.

The Birth of the Internet

In the 1960s, computers were only usually found in giant corporations and government offices. The military is also one major user of computer systems, and they discovered the need to access computers in remote bases from a central command, like the Pentagon.

While the standard telephone switch, which multiple telephone lines through a single operator connected-controlled switchboard, could work, it was vulnerable to attack and destruction, especially during the height of the cold war and the threat of nuclear war.

Hence, in 1966, the Advanced Research Projects Agency (ARPA) of the US Department of Defense began work on ARPANET’s development.

One of the concepts behind ARPANET was described by Bob Taylor, the Director of Information Processing Techniques Office at ARPA at that time, as follows. This was when he had three computer terminals (one terminal consisted of a monitor and keyboard—the computer itself was located elsewhere) in his office.

The computers were in separate locations, one in System Development Corporation in Santa Monica, California, another in UC Berkeley, and another in MIT. Taylor said:

For each of these three terminals, I had three different sets of user commands. So, if I was talking online with someone at SDC and I wanted to talk to someone I knew at Berkeley or MIT about this, I had to get up from the SDC terminal, go over and log into the other terminal, and get in touch with them. I said, “Oh Man!” it’s obvious what to do: If you have these three terminals, there ought to be one terminal that goes anywhere you want to go. That idea is the ARPANET.

Today, ARPANET still stands as the blueprint for the internet. The internet is not a single device—instead, it’s multiple massive networks of computers, like a hive mind, where different computers communicate with each other to deliver data where needed.

What It Means to “Go Online”

When you go online, it means you’re connecting to the internet. Before home broadband and Wi-Fi, computers weren’t automatically connected to the internet when you turned it on. After you boot up your PC, you use a modem to allow your computer to talk to your internet service provider (ISP) via your telephone line.

Once your computer and your ISP talks to each other, it establishes a connection, thus connecting your PC to the wider internet.

However, with the advent of fiber-optic technology, modems started to fall out of fashion—that’s why you no longer see them in your homes. Instead, many of us now have an optical network unit (ONU) to connect our computers to the internet.

Furthermore, most households now have more than one computer (your smartphone counts as one computer). That’s why most homes now require a router. Your computer will talk to your router, and the router will then talk to your modem (or ONU), which will then connect to your ISP.

Some routers already have a built-in modem, so you might not see one at home. Or it might already be built-in into your device, like your smartphone.

With the development of internet infrastructure and reduced costs, most of our devices are always online. For example, if your smartphone is always either connected to a data or Wi-Fi connection, it’s already online.

However, if you switch off these connections to save battery or data, you need to “go online” by manually toggling the switches that make your phone connect to the internet.

What Happens When You Visit a Webpage

Now that you have an introduction to what the internet is and what it means to connect to it, this is what actually happens when you visit a website. So, for this example, let’s say you’re visiting Google’s home page.

The page is stored on a web server. Your computer needs to access this server via your ISP so that you can load the Google home page on your browser.

You turn on your computer, log into your account, and then launch your browser. Then, on the address bar, you type the URL of the website you want to visit,, and hit enter.

Sending Requests From Your Computer to Your ISP

After you press enter, your computer starts talking to your ISP. It will tell your ISP that you’re looking for, so can it please look for it and send the data to your PC?

What Your Internet Service Provider Does

However, server addresses where the page you want to visit is stored doesn’t have a name. Instead, it has a numerical IP address, like Your ISP will search for the correct IP address through a domain name server (DNS).

A DNS is like a giant address book that matches website names with their numerical addresses. Once your ISP locates the correct IP address, it will then connect to that server and start sending your request.

Connecting to the Server and Requesting Data

Once your ISP locates the server where the website you want to visit is saved, it will send a request to connect to it. If the server approves the connection request, it will see that you’re asking to load the website for Google.

The server will then get the files saved on it and send them to your computer. In our example, you wanted to go to the Google homepage. The server where it’s saved will send the homepage to your computer.

Of course, it will not send the complete Google database to your computer—that would be nearly impossible to load. Instead, it will only send the data for that specific page. In the case of, it’s only the logo, your profile photo, plus a few other elements.

Loading the Data Into Your Computer

As your ISP receives the data from the server, it will start forwarding it to your computer as data packets. That means the data you asked for a broken down into smaller pieces, making it easier to transport.

As these packets arrive on your computer, they’re reassembled by your browser, allowing you to see the website you’re looking for.

A Tiny Drop In a Torrent of Internet Data

The example we gave above is a simplified version of the internet. In reality, when you’re visiting a website, your request can go through hundreds of nodes before it reaches your target destination. Your request is processed at the destination, and the requested data is sent back so your computer can load it.

This process happens with millions of computers connected to the internet, including desktops, laptops, and smartphones. And as we increasingly smarten our homes and utilize the Internet of Things, we can only expect internet connectivity and the data transferred through it to grow exponentially in the coming years.