How The Internet Works

Anupama Nair
The Patr-onus Deployment Blog

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The internet is a network of networks that consists of millions of computers worldwide.

When you’re on the internet, you can find almost anything you need if you know where to search. Computers and other devices connect to it through mediums like telephone lines or cables or wireless connections. This, you probably already knew. Now if you’re like me & weren’t paying attention in class when they told us how website requests work, this one’s for you.

First, let’s look at everything that’s involved in the process of searching for & retrieving a simple webpage.

  1. Client Browser
  2. A URL
  3. DNS Server
  4. Main Server / Host Server

Before we jump into how the whole thing works, let’s get the basics out of the way. So what is a webpage really? It is simply a means to display content or information on the internet. It’s not an application, but merely a collection of multimedia in an html format that can be easily shared with anyone on the internet.

There are a whole series of steps & procedures that go into a simple webpage request. So I’m going to split this into phases to make things a little simpler.

Phase 1:

Now when you want to access a webpage that is anywhere on the internet, you start by opening up the web browser on your computer. You either type in the URL of the website you wish to see or you search for it on google & find it that way.

When you hit enter, your browser then sends a request to one of several Domain Name Servers to retrieve the content you are looking for.

When you want to open any website in your browser, you need to ask for the webpage first. If you type a domain URL in your browser, it asks a name server to find out how to call up the corresponding web address. Once it gets the answer from the server, it sends a request for that page using HTTP

Phase 2:

A domain name server (DNS) is a computer that translates domain names into IP addresses.

A DNS resolution consists of two queries: an initial request and a subsequent response. The first query is sent by the client (you on your browser) to the server asking for the IP address corresponding to a given domain name, such as iamnoob.com; the second reply is sent from the DNS server back to the client with the IP address of iamnoob.com as well as other information such as where-to-look-ups and how-long-to-cache.

A DNS server can also be used as a local cache for other servers, meaning it may also have locally cached data about URLs that it has visited in the past and it may use this information to answer future requests. The DNS resolver that takes in & resolves your request is mostly managed by your ISP or Internet Service Provider.

The DNS resolver forwards your webpage request of iamnoob.com to a DNS root name server. Then the resolver forwards the request to one of the name servers (Top Level Domain DNS ) that specifically cater to “.com” names. The .com name server then identified the appropriate IP address of the server to forward the request to. This server would contain the actual files associated with iamnoob.com. The IP address is then returned to the resolver.

This IP address is then returned to the client browser.

Phase 3:

The browser makes an http request to the IP address that was returned via the DNS. This IP address is the “server” that hosts the webpage or webapp that you’re looking for. It may also contain other apps & sites. The server parses the request that has come in, it then deciphers which file needs to be shared.

The Web server returns the appropriate page to the IP address specified by the browser requesting the page. The page may also contain links to other files on the same server, such as images, which the browser will also request. The browser then takes the shared content & displays it on the client’s end.

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