Page 294 - DCAP101_BASIC_COMPUTER_SKILLS

Unit 14: Web Server Applications

Objectives Notes

After studying this unit, you will be able to:
• Understand the Web Server
• Explain the use and concept of E-mail
• Discuss instant messaging

• Explain internet telephony
• Understand video conference

Introduction

A web server is the combination of computer and the program installed on it. Web server
interacts with the client through a web browser. It delivers the web pages to the client and
to an application by using the web browser and the HTTP protocols respectively. We can
also define the web server as the package of large number of programs installed on a
computer connected to Internet or intranet for downloading the requested files using File
Transfer Protocol, serving e-mail and building and publishing web pages. A web server
works on a client server model. A computer connected to the Internet or intranet must have
a server program.

14.1 Web Server

A web server can be referred to as either the hardware (the computer) or the software (the
computer application) that helps to deliver content that can be accessed through the Internet.
The most common use of Web servers is to host Web sites but there are other uses like data
storage or for running enterprise applications.
14.1.1 Common Features
1. Virtual hosting to serve many Web sites using one IP address.
2. Large file support to be able to serve files whose size is greater than 2 GB on 32 bit
OS.
3. Bandwidth throttling to limit the speed of responses in order to not saturate the
network and to be able to serve more clients.
4. Server-side scripting to generate dynamic Web pages, still keeping Web server and
Web site implementations separate from each other.
14.1.2 Path Translation

Web servers are able to map the path component of a Uniform Resource Locator (URL) into:
A local file system resource (for static requests);
An internal or external program name (for dynamic requests).
For a static request the URL path specified by the client is relative to the Web server’s root
directory.
Consider the following URL as it would be requested by a client:
http://www.example.com/path/file.html
The client’s user agent will translate it into a connection to www.example.com with the
following HTTP 1.1 request:

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