A Study On The Http Proxy Server Computer Science Essay

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The system developed is a Proxy Server, which handles HTTP traffic only. This system takes an URL request from the client and it sends reply to the client based upon caching and filtering. If a web page is newly requested, the request is filtered first and then sends to parent proxy server in child Proxy Server mode. If the server started as main Proxy Server, the request is send directly to the web server. If the requested page is already available in the cache, then the server replies the client with the earlier page stored in the cache. Before sending the requested page to the client, the filtering operation (both site filtering and word filtering) is applied on that page. If that page is not in the filtered list, then only it is sending to the client, otherwise a warning message is send to the client.

This Proxy Server has the following features: This system is developed in JAVA and as such it benefits from cross-platform accessibility.


In today's world, Internet is playing crucial role. Everyone need Internet for Information gathering, communication and entertainment. A system can access Internet only if it has dedicated Internet connection. Any client system in the network(LAN) can't access Internet without a dedicated Internet Connection to each system; even the server has a Internet connection. One more problem is, if the system is directly connected to Internet, the viruses and worms in the Internet can attach the system. These problems can be overcome by the introduction of Proxy Server into the System which is connected to Internet.

Some home networks, corporate intranets, and Internet Service , Providers(ISPs) use proxy servers(also known as proxies).

This project has mainly three modules *J» Connection sharing «J* Caching *J* Filtering

The Connection sharing module provides shared Internet Access. A single Internet connection is proxied and is shared among multiple clients. That is rather than giving each client system an individual direct Internet Connection, a single connection is shared and all internal connections can be tunneled through the proxy system which is connected to the Internet.

The Caching module stores all the requested web pages in a local disc cache. Whenever a client requests a web page, the cache manager checks that page in the local cache, if it is available then the page is sent to the requested client, otherwise a request is made to the parent proxy in child proxy server mode. The server sends requests directly to the web server if it is started as main proxy server. After receiving the response, the page is cached in local cache and then it is forwarded to client.

The Filtering module filters all the requests made by the client. In this proxy server the filtering module has sub modules named site filtering and word filtering. In site filtering, whenever a client requests a web page, first the page is checked with in the restricted sites domain, if it is not in the restricted domain, then the request is forwarded to the cache manager. In word filtering, a page downloaded from parent proxy or web server is checked against the restricted the words domain. If the words in the downloaded page are matched with the words in the restricted list, warning message is forwarded to the client, otherwise a copy of the page is forwarded to the client and another copy is forwarded to the cache manager. The filtering feature makes the proxy server to act as a firewall.

Software Requirement Specification: Introduction

Purpose: The purpose of this document is to specify the functional and structural requirements of the system being developed.

Scope: This project handles only Http requests and other protocols like Telnet, SMTP, FTP are not implemented.

Intended Audience and Reading suggestions;

As this document is meant for acquire the requirements of the Project, it is useful to the persons like network Administrators who want o improve the use of the network Administrators who want to improve the use of the network bandwidth, control the network traffic and persons who want to improve this software, also the tester who test this software by keeping in mind of these improvements.

General Description

Product perspective: This HTTP Proxy Server is helpful in sharing a single Internet connection among multiple systems.

This application supports the catching of previously accessed web content.

It provides filter operations and restrict various sites specified by the user and restricts site that contains restricted words specified by the user. The Graphical User Interface (GUI) provided in this product is user-friendly.

Software Requirements

Java Jdk1.5