Your browser normally sends requests for pages directly to websites. Along with the request, it sends out your IP address (a unique identifier of your computer on the Internet, which can be tracked back to your country, city, ISP and finally to you).
The IP address of your computer is similar to the return address of a letter, to which the website sends all the pages and pictures you requested. If the return address is wrong, you will not be able to surf the Web. The only way to hide your true IP from the site you are visiting is to have a “middleman”, a computer that will take your requests from you and forward them to the website on your behalf; then it will receive the pages, pictures etc from the site and forward them to you. This way, the website will only know the IP address of that computer, called “proxy server”. By using different proxy servers you effectively change “your” IP address as it can be seen by the websites.
When you use A4Proxy, the browser sends all requests to A4Proxy, which redirects them to anonymous proxy servers in its database, and returns the pages received from them to your browser. In order to configure your browser in this way, you must enter 127.0.0.1 port 80 in its proxy settings. (Details for some popular browsers).
Address 127.0.0.1 is the address of your own machine, that is a special address, all calls to which are just returned back, sort of a loop. Port 80 is the port on which A4Proxy is sitting by default. So, 127.0.0.1 port 80 is the address of A4Proxy program on your own computer. After you have configured your browser in this way, A4Proxy will stand between your browser and the Internet, receiving requests for web pages from your browser and redirecting them to the anonymous proxy servers in its database. These proxy servers connect to the sites on your behalf and fetch the pages to A4Proxy, which then sends them to your browser to display. As a result, the websites see the IP address of the proxy server instead of your own IP address. This means that you are anonymous to the sites. As the actual data travel through the proxy servers in the database of A4Proxy, it is important to check them from time to time. Select all proxies and press the Check Proxy button, wait until all proxies are checked and then sort them by speed (click the Response time column header, the less the numbers the faster the proxy).
What happens if you shutdown A4Proxy now? The browser will still send all requests to the same address, 127.0.0.1 port 80, but now that you have closed A4Proxy, there’s no software at this address, and the connection fails.
A4Proxy works only with your web browser and download managers like GetRight. You can’t send anonymous e-mail with ordinary e-mail programs (but you can use web-based e-mail accounts like HotMail to send anonymous e-mail), and you can’t use it with chat programs or newsreader software. If you need anonymity for FTP (with standard FTP clients like CuteFTP), Usenet News (with standard newsreaders, e.g. Outlook or Agent), IRC (with standard IRC software like mIRC), ICQ and Email (POP/IMAP), have a look at our AntiFirewall product, AntiFirewall.com