A lot of people have been asking “What is Internet?”. Well this is a very broad question which can be answered in many different ways. In fact, a whole book could be written on the subject. In this article, I will attempt to break down the essence of the Internet in a nutshell. If you are reading this page, we assume that you know at least a little bit about the Internet (because you have reached this page through your web browser).
The Internet started as a science project called ARPANet by the United States defense department. Originally, it was a way for scientists and researchers to collaborate on important research through computers connected by wires. These connected computers were known as a network. Most of the computers on this network were large mainframe computers which each ran a common operating system.
Shortly thereafter, e-mail was invented as a way to send private messages between one individual and another. This was the first “killer app” that really catapulted the Internet into the mainstream. Using this system, one individual could contact another or another whole group of people and have discussions on topics that were important to them. Later on, attachments allowed people to deliver documents through the computer network and share valuable research.
Over the years, the same network was adopted by colleges and universities so scientists and researchers at those institutions could also share their knowledge over the network. One of the first means of communicating was the Usenet newsgroups which is like a message board for various different topics. Usenet newsgroups are still around today although certain ISPs choose to block them since they have been used extensively for file sharing in recent years.
With the advent of the personal computer and a graphical user environment (Apple Macintosh and Microsoft Windows), it wasn’t long before the Internet came to home users. One of the most important inventions during this time was the concept of the World Wide Web and the Hypertext Markup Language. A small company called Mosaic developed software that allowed users to view documents over the Internet. This company later became Netscape which initially dominated the web browser marketplace.
So enough about the history, now lets talk about how the Internet works. Each computer on the network is called a node. Each of these nodes has a unique address. This IP or Internet Protocol address is unique for every computer on the entire Internet. It consists of four bytes (with a byte being a number between 0 and 255). When one computer wants to talk to another using an IP address, it simply looks up the address and makes a connection. Actually, it’s not quite that simple.
In order for a computer to find another computer by IP, it needs to have a route (or road map) because not every computer has a direct connection to every other computer. A route consists of a path through different nodes in the network that lead to the desired computer. To get this route, a computer consults a gateway which forwards each request to the next node in the chain. So how does it know which node is the next in the chain? Well each gateway has its own authority which it consults. This happens repeatedly going higher and higher until the proper authority is located with the answer.
Early on, it was decided that accessing computers using a series of four numbers was not a very efficient way to work. So engineers developed what is known as a Domain Name System or DNS. This allowed users to use a letters and digits for a remote address. Special computers were dedicated to managing domain names with a central server designated as the ultimate authority for names. This ultimate authority is known as ICANN or the Internet Corporation for Assigned Names and Numbers.
In order to make domain name lookup as efficient as possible, DNS servers are distributed across the Internet. Each one is an authority for many different IPs, but ultimately, must be subservient to the root authority server. This root authority server is the centralized registry of all domain names. Without this system of domain names, the Internet would not be what it is today. Nearly everything we do on the Internet revolves around the Domain Name System.
Without going into the specifics of how routing works, we hope that we have given you a good overview of What is Internet and how it works. Some of the related technologies that we haven’t discussed are: FTP, SSH, Telnet, Ping, IRC, Nslookup, and Domain Registrars. In the future we will address these specific technologies to help you get up to speed. As we mentioned at the start, this is a broad topic and no single blog post can cover all of these subjects.