What is a web server and which is the best?

A web server actually refers to two things - a computer/machine that hosts web sites (hardware) and a software that runs on such a machine and processes requests from browsers (also called client software). Thus, if someone mentions "web server", you need to clarify - Are they referring to the machine or the software?

In this article I shall provide some information on web server software. If you want details on web server machine, I suggest you read "how is a web hosting Server different from your home/office machine?"

A web server is special software capable of servicing HTTP (Hypertext Transfer Protocol) requests. For this reason, web server software is also referred to as HTTP server.

OK... in English.

A web server is a program (software) helps serve web pages when they are requested for by browsers. The web server runs the HyperText Transfer Protocol which is a set of rules for two computers to talk to each other.
[And that was my best attempt at putting it in the simplest language possible].

So when you open a web site in your browser (called the client software), a request is sent to the web server on a remote machine. This web server software processes your browser's request and tries to locate the web page. If it finds it, the web server sends the web page to your browser which then displays it.

Popular web servers

According to Netcraft web server usage survey, Apache HTTP server is the most popular web server with a large market share of almost 60%. The popularity of Apache is followed by Microsoft's web server. The share of other web servers is very small compared to these two. Refer the Netcraft web server survey for further details.

Can you run a web server on your computer?

Oh yes! For example, I run the Apache web server on my Windows XP computer. I do this to test the scripts I write (in PHP and Perl) for web sites before I put them online. I find this process easier and quicker than trying to work off a remote server. So if you are planning to develop a web site that runs PHP or Perl scripts, I would definitely recommend that you get a copy of the Apache web server and install it on your system.

Finally, to know which server your site is running on check it with Netcraft's What's that site running on? Tool.