What happens when you type holbertonschool.com in your browser and press Enter

Have you ever wondered how your computer does to bring the web page you want?
for example, do you know what happens when you type www.holbertonschool.com?
It is a simple but complex process and to understand it we are going to divide it into parts, let’s start by knowing:

What is a browser?

A web browser (commonly referred to as a browser) is application software for accessing the World Wide Web. When a user requests a web page from a particular website, the web browser retrieves the necessary content from a web server and then displays the page on the user’s device.

A web browser is not the same thing as a search engine, though the two are often confused. A search engine is a website that provides links to other websites. However, to connect to a website’s server and display its web pages, a user must have a web browser installed

DNS lookup

The DNS is the Internet’s version of Google Maps. It routes you to your destination. Your computer or your router knows the address of the DNS server. When you type the URL in a browser for the first time, it sends a request to the DNS server, which responds back with the IP address of the web server hosting, for example, holbertonschool.com. This value is usually then cached or gets added into the list of known hosts, so your browser doesn’t have to do this lookup every time.

Web server

A web server is computer software and underlying hardware that accepts requests via HTTP, the network protocol created to distribute web pages, or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a specific resource using HTTP, and the server responds with the content of that resource or an error message. The server can also accept and store resources sent from the user agent if configured to do so.

A server can be a single computer, or even an embedded system such as a router with a built-in configuration interface, but high-traffic websites typically run web servers on fleets of computers designed to handle large numbers of requests for documents, multimedia files and interactive scripts. A resource sent from a web server can be a preexisting file available to the server, or it can be generated at the time of the request by another program that communicates with the server program. The former is often faster and more easily cached for repeated requests, while the latter supports a broader range of applications. Websites that serve generated content usually incorporate stored files whenever possible.

A server can be a single computer, or even an embedded system such as a router with a built-in configuration interface, but high-traffic websites typically run web servers on fleets of computers designed to handle large numbers of requests for documents, multimedia files and interactive scripts. A resource sent from a web server can be a preexisting file available to the server, or it can be generated at the time of the request by another program that communicates with the server program. The former is often faster and more easily cached for repeated requests, while the latter supports a broader range of applications. Websites that serve generated content usually incorporate stored files whenever possible.

Load balancing

Popular websites have to serve several thousands of concurrent requests and return correct text, image and video responses to them. To serve a large number of requests, the content is usually distributed across multiple servers. A load balancer sits in front of these servers and acts as a traffic cop to direct traffic to the right server. It makes sure that no server is overloaded, and provides high availability and reliability by ensuring all requests are served. If a server goes down, it starts redirecting the requests to different servers that are online.