What is a Web Server ?
Web Servers are computers on the Internet that are used to host websites, emails, stores files, run online applications, etc. This service is referred to as Web Hosting. Every Web Server has a unique address so that other computers connected to the internet know where to find it on the vast network. The Internet Protocol (IP) address looks something like this: XXX.XXX.XXX.XXX. This address maps to a more human-friendly address, such as http://www.pentame.com.
Web Hosts rent out space on their Web Servers or a Full Server itself to people or businesses to set up their own websites, To host email, or run Custom applications etc. The Web Server allocates a unique website address to each website it hosts.
When someone connects to the Internet, his personal computer also receives a unique IP address assigned by his Internet Service Provider (ISP). This address identifies the computer's location on the network. When he clicks on a link to visit a website, like www.pentame.com, his browser sends out a request to www.pentame.com IP address. This request includes return information and functions like a postal letter sent across town, but in this case the information is transferred across a network. The communiqué passes through several computers on the way to www.pentame.com, each routing it closer to its ultimate destination.
Web Server is not just a "big" machine sitting somewhere in the server room with big processing power and memory.
Whole Web Server = Computer Hardware + Operating System + Web Server Software + Info Content