A Web server is a software program which serves web pages to web users (browsers).
A web server delivers requested web pages to users who enter the URL in a web browser. Every computer on the Internet that contains a web site must have a web server program.
The computer in which a web server program runs is also usually called a “web server”. So, the term “web server” is used to represent both the server program and the computer in which the server program runs.
Characteristics of web servers
A web server computer is just like any other computer. The basic characteristics of web servers are:
- It is always connected to the internet so that clients can access the web pages hosted by the web server.
- It has an application called ‘web server’ running always.
In short, a ‘web server’ is a computer which is connected to the internet/intranet and has a software called ‘web server’. The web server program will be always running in the computer. When any user try to access a website hosted by the web server, it is actually the web server program which delivers the web page which client asks for.
All web sites in the internet are hosted in some web servers sitting in different parts of the world.
Web Server is a hardware or a software?
From the above definition, you must have landed up in confusion “Web server is a hardware or a software”
Mostly, Web server refers to the software program, which serves the clients request. But as we mentioned earlier in this chapter, the computer in which the web server program is also called ‘web server”.
Web Server – Behind the Scene
Now that you are reading this page, have you ever had a thought how the page is made available to the browser?
Your answer would be, “I typed in the URL http://www.aspspider.com and clicked on some link, I dropped into this page.”
But what happen behind the scenes to bring you to this page and make you read this line of text.
So now, lets see what is actually happening behind the scene. The first you did is, you typed the URL http://www.planetofcoders.com in the address bar of your browser and pressed your return key.
We could break this URL into two parts,
- The protocol we are going to use to connect to the server (http)
- The server name (www.planetofcoders.com)
The browser breaks up the URL into these parts and then it tries to communicate with the server looking up for the server name. Actually, server is identified through an IP address but the alias for the IP address is maintained in the DNS Server or the Naming server. The browser looks up these naming servers, identifies the IP address of the server requested and gets the site and gets the HTML tags for the web page. Finally it displays the HTML Content in the browser.
Where is my web server?
When you try to access a web site, you don’t really need to know where the web server is located. The web server may be located in another city or country, but all you need to do is, type the URL of the web site you want to access in a web browser. The web browser will send this information to the internet and find the web server. Once the web server is located, it will request the specific web page from the web-server program running in the server. Web server program will process your request and send the resulting web page to your browser. It is the responsibility of your browser to format and display the webpage to you.
How many web servers are needed for a web site?
Typically, there is only one web server required for a web site. But large web sites like Yahoo, Google, MSN etc will have millions of visitors every minute. One computer cannot process such huge numbers of requests. So, they will have hundreds of servers deployed in different parts of the world so that can provide a faster response.
How many websites can be hosted in one server?
A web server can hosted hundreds of web sites. Most of the small web sites in the internet are hosted on shared web servers. There are several web hosting companies who offer shared web hosting. If you buy a shared web hosting from a web hosting company, they will host your web site in their web server along with several other web sites for a Fee.
Examples of web server applications
- IIS
- Apache