The Internet is an inexhaustible source of information for us. And all we have to do, if we want a piece of information, is to search the Internet to get the answer we want.
But who provides us with this information and how? All this is possible thanks to what is called the Web server. This machine responds to computer requests from our browsers, also called Web Clients.
Web servers are essentially simple computer programs that deliver the web page at the request of the web client. The machines on which this program is run are generally called servers, with the names web server and server being used almost interchangeably.
These servers communicate with the clients to which they are connected using a computer protocol and language (HTML) that “travels” over the Internet. This is how we can use the Web.
It is also on these servers that your valuable data is stored.
Generally, when we think of web servers, many people think of them as very powerful computers, which is sometimes correct in that some very powerful computers are also called web servers. But these computers are built with the sole purpose of web hosting many sites (this is called shared hosting). However, when someone refers to a web server, it mainly means the software that can be downloaded to a more or less powerful machine (you can create a web server on your home computer).
When do you need a web server?
Typically, web servers are used by web hosting companies and professional web application developers. But, in reality, anyone who fits one of the categories below can use it.
Anyone who owns a website and wants to share it on the Internet.
Anyone who wants to use server-side technologies, such as PHP, ASP or ColdFusion, for application development, training or entertainment.
How do Web servers work?
This process consists of 4 steps, which are :
Obtain the IP address of the domain name: our web browser first obtains the IP address to which the domain name is attached. It can get the IP address in two ways-
By searching its cache.
By asking one or more DNS (Domain Name System) servers.
Note: an IP address is assigned to every website when it is created on the web server.
The browser asks for the complete URL: after having known the IP address, the browser now asks the Web server for a complete URL.
The Web server responds to the request: the Web server responds to the browser by sending the desired pages. If the pages do not exist or if another error occurs, it sends the appropriate error message.
For example: You may have seen the 404 error when trying to open a web page, which is the message sent by the server when the page does not exist.
Error 401 is another common problem when we are denied access due to incorrect credentials, such as username or password.
Browser displays the web page: The browser retrieves the web pages and displays them or displays the error message.
Popular Web Servers
There are many web server software, such as Apache, Microsoft IIS, Nginx Web Server, LightSpeed Web Server. But, the two most popular are:
Apache HTTP Server: This is the most common and widely used web server. It is developed and maintained by Apache Software Foundation. The software is produced under the Apache license, which makes it free and open source.
It is available for various operating systems: Windows, Mac OS X, Unix, Linux, Solaris, Novell Netware and FreeBSD.
Microsoft Internet Information Service: Microsoft IIS (Internet Information Service) is the second most used Web server. Its market share is growing rapidly every day and it is likely to overtake Apache in the coming years.
The IIS server has all the features of Apache, but it is not open source. Developed and maintained by Microsoft, it therefore works with all Windows operating system platforms.
The Linux / Apache / MySQL / PHP (LAMP) software server combination is the most common, but there are many others that are just as powerful (IIS and Zope for example).
In summary, Web servers can be used by an individual or by companies. The website can be accessed by anyone in the world (if the software is configured to allow it).
The necessary power of a Web server
We have seen that a Web server can be implemented by an individual, by companies or by hosting companies. The three uses will not require the same power.
A company can have its own server in its premises or use a hosting company.
It is easy to imagine that a professional host will install many Web sites on the same machine (mutualization). He will therefore need powerful machines that he will install in a network in a datacenter so that the response times are satisfactory for Internet users but also for Google.
However, this is not often what we observe: low-cost shared hosting (a hundred dollars a year) is often incompatible with professional Internet use (e-commerce, acquisition of leads).
Indeed, the machines are undersized, the number of sites hosted on each machine is too high or the distribution of sites on the same machine is not well calibrated. When a high-traffic site and smaller sites coexist on the same server, the resources are mostly taken up by the big site, which penalizes the small sites that become slow. And that, Google does not like at all…
