Web Proxy Server

Table of Contents

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Overview

Web proxy server is a server that provides Web access on behalf of the user . This section explains the purpose of using a Web proxy server, how it works, and its configuration on Windows.

What is Web Proxy Server?

When viewing a Web page, the interaction between the Web browser and the Web server application takes place, sometimes with a proxy server in between. Proxy server is a server that provides access to a Web site on behalf of the user. It is often described as a “web proxy server” to emphasize that it performs web access on behalf of the user.

Purpose of using proxy server

There are three main purposes for deploying proxy server.

Concealing the source of access
Check the Web sites you are accessing
Prevent access to malicious websites (URL filtering)

In the past, proxy servers were sometimes deployed to cache Web site data to speed up Web access.

Concealing the source of access

One of the purposes of using proxy server is to conceal the access source. In Web access via a proxy server, the access source (source IP address) becomes the proxy server for the Web server, and the original client PC is unknown.

When a cracker with malicious intent conducts some kind of attack, he or she tries to hide his or her identity as much as possible. One way to achieve this is through proxy servers. By going through multiple proxy servers, it becomes easier to conceal one’s identity. However, it does not mean that the access source can be completely concealed.

Check the Web sites you are accessing

By using proxy servers, it is possible to check what websites are being accessed from the web browsers of client PCs.

With a proxy server, it is possible to check what websites are being accessed from each client PC’s web browser. Thus, it is possible to check whether employees are accessing websites that are not related to their work.

Figure: Check the Web sites you are accessing

Prevent access to malicious websites (URL filtering)

Using proxy server, access to malicious Web sites can be restricted, which is referred to as URL filtering or Web filtering.

URL filtering prevents access to websites that are unnecessary for business or offensive to public order and morals, such as adult sites.

Figure: Prevent access to malicious websites (URL filtering)

Web access via proxy server

Let’s consider the flow of web access via proxy server.

First, a proxy server must be prepared. To make the server work as a proxy server, a proxy server application is started on the server. Then, the proxy server is configured on the client PC.

Web access from a client PC via proxy server is as follows.

HTTP request is sent to the proxy server when a URL is entered in a web browser on the client PC.
Send HTTP request from proxy server to web server specified by URL
Web server sends HTTP response to proxy server
HTTP response is sent from the proxy server to the client PC’s Web browser

Note that the TCP port number 8080 is often used when accessing the proxy server from a client PC’s Web browser.

Proxy Server Configuration(Windows OS)

The configuration for web access via proxy server on Windows OS is as follows

Open the proxy configuration window.
Specify the IP address and port number of the proxy server

1.Open the proxy configuration window.

Open the proxy configuration window. [Settings] -> [Network & Internet] -> [Proxy]

2. Specify the IP address and port number of the proxy server

Under [Manual proxy setup”, turn on “Use a proxy server” and specify the IP address and port number of the proxy server. The administrator should inform you of the IP address and port number you should specify.

Summary

Points

Web proxy server is a server that performs Web access on behalf of the user.
The main purposes of using proxy server are as follows
- Concealing the source of access
- Check the Web sites you are accessing
- Prevent access to malicious websites (URL filtering)