What is a web server?
What is an http server?
You have inevitably seen it when you surf, the addresses of the sites start with http, this makes it possible to reach the web server.
Do you know what this is?
You will see that we are talking about one of the most used protocols on the Internet. It is a protocol that you use every day, without necessarily knowing it.
So let’s take a closer look at the protocol and http servers, also called web servers.
Global principle of http
To get started, let’s take a look at how internet surfing is going.
To surf the web, you use an Internet browser. Depending on your clicks or your entries, it will call up pages contained on servers, retrieve them and display them.
The server waits for connections and requests, it just responds to the request by sending content. (we will see a little later, that it can also receive some).
Reminder on protocols and services
Before continuing and looking at how it works in detail, let’s start with a little reminder. To connect to a server, you use one or more ports (front door) and a protocol (language used). (well when I say you, you don’t do it directly, but the software you use does it)
The notion of URI and URL.
In general, surfing begins with an address, whether you entered it directly, or whatever the result of a search engine (which is also launched by an address such as http: // www. google.com ), you always need an address to go somewhere. To reach an http server, it’s the same: we use an address.
An Internet address is always made up as follows:
protocol : // server-address : port / path / resource
(note that the port, path and resource can then be omitted, so the default values will be used).
Let’s take a closer look at the address currently displayed in your browser:
(be careful, some browsers do not display http: //, they consider that http being the default standard, it is not necessary to display it, but it is there, believe me)
This address is called URL ( Uniform Resource Locator: We can translate this by a universal means of locating a resource.). Just remember that a URL is an address.
This URL designates and contains several information:
Protocol of the web server:
http or https: This is the protocol that will be used by the browser to access the server and send it these requests. For 2 people to understand each other, they must speak the same language. Well in computer science, it’s the same: the browser must know in which language it must speak to the server. This language is called protocol.
Address of the web Server:
www.wbsofts.com: This is the address of the server. There are millions of servers on the Internet, your computer will not address itself to any server, but it will access the server containing the “wbsofts.com” site. (I remind you that to know where the server contains “www.wbsofts.com“, the computer will make a DNS request: see What is a DNS server?)
And if we are talking about the resource to retrieve or access, we will talk about URI (Uniform Resource Identifier)
this-what-an-http-server-or-web-server: This is the resource that we want to retrieve from the server. We can add the access path in the server.
This resource might be a page like the one currently displayed on your computer, but it could be something else like
This might be a piece of music, a download file, etc.
Definition of http
Now is the time to focus more specifically on the http protocol and the http web server.
First of all, what does http mean?
http: is the abbreviation for HyperText Transfer Protocol. So, clearly a hypertext transfer protocol! I am not sure that with the translation it is much clearer, except that we understand that it is used to transfer HyperText. But what is hypertext?
What is hypertext?
Hypertext: a hypertext is a text containing links which allow direct access to other resources (documents, images, etc.). If we look closely, the pages that are displayed in your browser are hypertext because they contain links (to URLs).
Definition of the GENERAL COMMISSION OF TERMINOLOGY AND NEOLOGY
Field: Computing / Internet.
Definition: System of references allowing to go directly from one part of a document to another, or from one document to other documents chosen as relevant by the author.
Foreign equivalent: hypertext.
Port used in http
I reminded you above: who says protocol says port. The default port to access an http server, the port is 80. However, browsers are able to communicate with an http server on different ports (on condition of course to tell them and that the server waits to dialogue on another port).
This technique with different ports is used to reach servers in different ways:
With the default port, you consult the pages made available by the server.
With a different port, you access other pages that cannot be accessed directly, such as server administration pages for example.
But it is also possible to have several different sites on the same server. Access to one or other of the sites will depend on the port addressed.