In the context of firewall as a nonbiometric security measure, a is software that acts as an intermediary between two systems.

Proxy Server                        

Explanation:

Proxy server is a server that acts as a mediator between two systems.One system can be your computer and the other can be the server to which you are asking a service, such as requesting a web page. Lets suppose you request a web page from a server and you type a URL of a website to access a web page. This request goes to proxy server which sends this request on your behalf to the target server in order to retrieve that web page. Proxy server makes this request to the target server on the internet by using one of its IP addresses. When the proxy server gets that web page, it will forward that web page to your requesting computer. If you request a specific service such as a website frequently the proxy server saves that website on its cache. So if you request that website again, proxy server will forward it to you from its cache rather than requesting it again from the target server on your behalf resulting in quick response to the user's request.Proxy servers provide users with privacy to access the websites, and they can surf the internet anonymously .

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