Web Servers: Before we can get into the process of analyzing and hacking web servers as well as applications, we must look at the web servers themselves.
In the simplest terms, a web server is a software package that is designed to deliver files and content over HTTP.
These files are delivered in response to request that come from clients in software form.
Web servers are part of a larger family of Internet- and intranet-based programs that deliver content such as email, files, web pages, and other types.
While all web servers deliver the same basic types of content such as HTML, they can vary in their support for application extensions and other technologies,
Web servers are differentiated y operating system support, server-side technologies, security models, client support, development tools, and many more factors.
Currently, there exist a staggering number of web server technologies, but to keep things realistic and practical we will concentrate on only the market leaders: Microsoft’s Internet Information Server (IIS) and Apache on Linux and Unix.
NOTE: In the real world, the leading web server technologies are Apache, IIS, and ngix, which runs on numerous operating systems. To be fair there are other web server technologies such as Novell NetWare server, Google Web Server, and Domino servers from IBM. While no list of web servers is complete, in most cases it doesn’t have to be because the technologies you are likely to encounter in this space tend to be fairly limited.
However, when you do encounter an unusual server you should be prepared to do your research. Who knows? You may run into a customer who is still running a version of Netscape’s Web Server technology, though I hope not.