How Does a Web Proxy Work?

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Category: Internet Security

Published on Thursday, 14 March 2013 16:08

Written by Eric

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Surely you have heard many times the term proxy, but you didn't know what it really is and what it does. If you are accessing the Internet from a computer located in a network or an office environment, almost certainly your communications passed through the proxy. But, what is a proxy? Simply: proxy is a layer of software that does the job for a network client. Network client creates the request, and the server responds to the request. For example, your web browser requires web content from a web server: depending on the proxy there are several ways of how proxy might work for the client, and they can be different: reverse proxy, arp proxy, transparent etc. We can understand this when we are visiting a particular website. For instance "www.google.com". At the bottom, browser displays a message: "Waiting for www.google.com". That means our web reader connects directly with the specified web server. But if it shows something like "Connecting to 192.171.1.1..." then our communication goes through a proxy.

What are the advantages of using a proxy?

Firstly, the only computer on the network that must have a public IP address is the one on which the proxy is located. In the same time, that means that whole network can have access to the Internet (and it gains safety on the network also). The proxy also improves the flow of informations retaining in its cache memory requests of earlier readers. For example, if a user has requested some sort of page, the proxy will copy the contents of its cache. When the next request for that same page arrives to proxy, it shall content from its cache instead of going back to the Internet to download the requested web page. It is important to note that protected content will not be copied into the cache memory. For example, if you give information about your credit card on the site with URL which starts with "https://", this information will not be stored in the cache of the proxy. Another way in which proxy works "for the sake of" client is as a "transparent" proxy. But, let's say something about third term: reverse proxy. When user requests information on the Internet by a web server protected by reverse proxy, reverse proxy intercepts the request and checks whether the information contained in the application are acceptable data (such as malicious HTTP commands), and that means: the most common use of reverse proxy is to protect web server.