3.6. Identifying the Purpose, Benefits, and Characteristics of Using a Proxy Service

The term "proxy" is defined as the function or authority of acting for another. It can be used in legal settings, where a person is given the authority to be the proxy for another person and to therefore act on that person's behalf. In computer terminology, a proxy service is a service that makes a connection to the Internet on behalf of a user. The proxy service provides many benefits to an organization by making the Internet connection instead of letting each client make its own connections.

3.6.1. Critical Information

You should understand the purpose of a proxy service. In addition, you should understand the main benefits that a proxy service provides an organization. Finally, you should understand what is involved in using a proxy service and the special configuration that will be required for clients to use the proxy service.

3.6.1.1. The Purpose of a Proxy Service

The main purpose of a proxy service is to make Internet connections on behalf of the clients in a network. It is positioned between the clients and the Internet, and it intercepts the client's Internet requests and makes the request on behalf of the client. Clients are configured to use the proxy service to make the connection instead of making the connection on their own. We will discuss this configuration in greater depth later in this section.

3.6.1.2. The Benefits of a Proxy Service

Since the proxy service is in between the Internet and clients, it can provide many benefits to the organization as a whole. The main benefits that the proxy service provides are as follows:

Improved performance

Since the proxy service caches all of the requests that go through it, it can often quickly resolve an IP address from a hostname without any DNS servers. If many clients in the network tend to use the same pages, these pages are often already in the cache when the clients requests them.

Improved control

Since the proxy service makes the request on behalf of the client, it can be configured to only make specific requests for specific clients at specified times. For example, an organization could use a proxy service to keep specified groups of users from browsing the Internet from 9:00 a.m. to 4:00 p.m. but allow it at all other times. Likewise, all clients could be prevented from browsing specified sites on the Internet if those sites are deemed inappropriate.

Reporting

Since the proxy service makes the requests on behalf of the client, it can also keep a detailed record of all of the requests that it makes. This record can contain such information as the name of the client, the requested site, and the time that the request was made. The report can include information about requests that were granted as well as those that were not granted. This type of information can be helpful to the Human Resources department of an organization if they are building a case against someone who is using the Internet in an inappropriate manner.

3.6.1.3. Considerations when Using a Proxy Service

If a proxy service is used in a network, the clients will need to be configured to use the proxy service. The exact configuration of the clients will depend on what client is used, but it will likely be found in the browser settings on the client. In Windows XP Professional, for example, you can find the configuration settings for using a proxy service in the Local Area Network (LAN) Settings screen in Internet Explorer (see Figure 3.9). (To open this screen, choose Internet Options from the Tools menu, select the Connections tab, and click the LAN Settings button.) You can configure the client computers to automatically detect a proxy server, or you can manually configure the address and port of the proxy server. You should also check the option Bypass Proxy Server for Local Addresses if your clients will also be using sites within your own intranet.

Figure 3.9. The LAN Settings screen in Internet Explorer

3.6.2. Exam Essentials

Describe the purpose of a proxy service. The main purpose of a proxy service is to make Internet requests on behalf of a client.

List the benefits of a proxy service. A proxy service provides many benefits for a client, including improved performance and detailed reporting. The proxy service can provide these benefits because it caches client requests when it receives them. The proxy service can provide improved control and can prevent groups of clients from accessing specified sites or from browsing the Web at specified times.

Know how to use a proxy service. Clients must be configured to use a proxy service. This configuration will likely be part of the client's browser configuration settings. Clients can usually be configured to automatically detect a proxy server, or they can be manually configured with the address and port of the server.