AuthorNtokozo Zwane, Software Engineer, Rapid7 How did this blog end up on your computer? Your answer is likely something along the lines of, “I clicked the link and my browser fetched the page from the internet and loaded it up for me”. Hopefully, by the end of this short post, we will demystify the entire process, by digging into what the internet is, where to find it and how to break it. You have probably heard the internet being referred to as ‘the cloud’, but this analogy doesn’t accurately capture what it looks like in reality. A more realistic image of what the internet is would be to think of it as a really long wire - an actual physical wire. Multiple devices are then able to communicate to each other by simply connecting (directly or indirectly) to this wire. Computers that are connected directly to the wire are called servers. This is typically where files for websites are stored. In the case of this blog, it is currently stored on a server just outside Wichita, in the United States. Unlike servers, your computer or phone connects to the wire indirectly through an internet service provider (ISP). Each country would have a number of national ISPs (e.g Telkom, Afrihost, rain or eir broadband). The national ISPs are able to connect directly to servers within their home country. In order to reach a server in a different country, your country’s national ISPs need to connect to the ISPs in the country where that server is found. ISPs act like mediators, since they have the necessary infrastructure to communicate with other servers and ISPs that are connected to the wire. This means you do not have to manually connect to each server or ISP yourself. Now back to the server near Wichita that this blog is sitting on. How does it land up on the screen in front of you? Since there are billions of computers, servers and ISPs (we’ll just call these devices) connected to the wire, there needs to be a process to ensure that information travels between the correct devices. The first step is to give each and every device a unique identifier - much like your government ID number. This is the device’s IP address, and at each intersection point of the wire, exists a special type of device that figures out where to send information based on this identifier, this is called a router. IP addresses are hard to remember, and it would be really inconvenient if you had to type in 199.34.228.53 every time you wanted to visit this blog. Instead of using the IP address, we give them friendly names that are easier to consume by humans, such as takealot.co.za and twitter.com. For this blog, the IP address 199.34.228.53 is given the name, reazwane.weebly.com. Bringing this all together, when you came over here through the following link/url reazwane.weebly.com/science-for-a-lay, the first step was your browser looking up the IP address that the url belongs to. Once that was established, it sent a message to the server to ask it for this blog page. This message was then carried along the different components of the wire, and the routers directed it to the correct destination. Once the server near Wichita received your message, it interpreted it and replied with the information you asked for. The blog post was then sent (in tiny chunks) back to your browser. The crux of this all working is that all these different components need to use the same language (protocol) to communicate with each other. A group of computers that communicates together using a common protocol is a called network. The term internet is formed by inter-, meaning between, and net, short for network. It is a global network of computers that speak a common language, connected by the wire - a long physical wire, 1.2 million km of which sits at the bottom of the ocean to enable intercontinental communication.
So next time you really want to break the internet, grab a wetsuit and some wire cutters ;).
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