What is Proxy?
A proxy or proxy server is basically another computer which serves as a hub through which internet requests are processed. By connecting through one of these servers, your computer sends your requests to the proxy server which then processes your request and returns what you were wanting. In this way it serves as an intermediary between your home machine and the rest of the computers on the internet. Proxies are used for a number of reasons such as to filter web content, to go around restrictions such as parental blocks, to screen downloads and uploads and to provide anonymity when surfing the internet.
Why Use a Proxy?
If you are wanting to surf the web anonymously then proxies can provide you with a means to hide your home IP address from the rest of the world. By connecting to the internet through proxies, the home IP address of your machine will not be shown but rather the IP of the proxy server will be shown. This can provide you with more privacy then if you were simply connecting directly to the internet. There are number of proxies that can provide you with service. You can find a list of these simply by typing “Proxy List” into any search engine. There are some proxies which are free and some which charge money, the choice is up to you but we have found that the paid proxies are more reliable, faster and more secure.
Source
Firefox adds-on for hiding IP using Proxy:
Foxy Proxy Standard
After you installed, restart your FireFox browser.
Tutorial how to use this adds-on, watch this video: