A web server is a program that uses http to derve the files that form web pages, in response to the requests, which are forwaded by their computers http client. It is mostly designed to serve static content, though most web sever have plugin to support scripting language like Perl, PHP, ASP, JSP etc through which these servers can generate dynamic http content.
Web Servers:
* Apache HTTP Server(by Apache)
* Internet Information Services(by Microsoft)
* Sun Java system web serve