What is the web server?
Web servers are computers that deliver (serves up) Web pages. Every Web server has an IP address and possibly a domain name. For example, if you enter the URL "http://joomtut.com" in your browser, this sends a request to the Web server whose domain name is joomtut.com. The server then fetches the index page (named: index.html, index.php or index.asp,...) in and sends it to your browser.
Any computer can be turned into a Web server by installing server software and connecting the machine to the Internet. There are many Web server software applications, including public domain software from NCSA and Apache, and commercial packages from Microsoft, Netscape and others.
How do web servers work?
Typically, users visit a Web site by either clicking on a hyperlink that brings them to that site or keying the site's URL directly into the address bar of a browser. But how does the same site appear on anyone's computer anywhere in the world and often on many computers at the same time?
Let's use joomtut as an example. You decide to visit joomtut by typing its URL "http://joomtut.com" (or joomtut.com) into your Web browser. Through an Internet connection, your browser initiates a connection to the Web server that is storing the joomtut files by first converting the domain name into an IP address (through a domain name service) and then locating the server that is storing the information for that IP address (also see Understanding IP Addressing).
The Web server stores all of the files necessary to display joomtut's pages on your computer typically all the individual pages that comprise the entirety of a Web site, any images/graphic files and any scripts that make dynamic elements of the site function.
Once contact has been made, the browser requests the data from the Web server, and using HTTP, the server delivers the data back to your browser. The browser in turn converts, or formats, the computer languages that the files are made up of into what you see displayed in your browser. In the same way the server can send the files to many client computers at the same time, allowing multiple clients to view the same page simultaneously.
What is web hosting?
To make your website available to the public, you need a web server to essentially host or house your website.
Web hosting is a service where a web hosting provider grants you space on a web server that houses your website and makes it available for viewing on the web.
A website has to be placed on a web server that has a dedicated connection to the web so that web users can successfully view it 24 hours a day, 7 days a week.