When you open a web page, all sorts of things will need to be done in the background before you get your shiny website on your screen.
We will see now what is happening in the networking system to make that possible.
TCP/IP protocol is what makes sending and receiving most of the data across the Internet possible. But how data packets know how to find us and how we know how to find the IP addresses of the web servers where these pages are saved?
Data will maybe not even take the same route in each direction. It can happen that when we send something, a request to the server, the packets will flow through one route and the server response towards our computer will take some other route.
The Internet is the biggest computer networking system. It knows in every moment how to find the best route to some device connected anywhere in-between all his nodes.
But how is this data transferred across the wires, fibres and air?
Data is divided into small packets. Every time we send a request towards a server, our request must firstly be divided into packets, most of the same size. Each of those packets needs an IP address of the destination to be written on it so that he can be routed through the network.
In order to find out what is the destination IP address of the server – (remember that we are typing an URL into the browser, usually we are not typing IP address into it) – your computer, before sending out all those packets, will contact public DNS server – domain name server, that will have the information about IP address to which packets must be forwarded in order to get to your URL-linked page.
Public DNS servers are set up into a hierarchical system that keeps the knowledge of IP addresses for all URLs (domain names) that are registered on the Internet. With this database, DNS is able to translate our request for the web page URL into the IP address of the server on which the web page is stored.