Every computer on the Internet needs a unique Internet protocol (IP) address. Use this IP address as your computer's street address. Just as the post office knows how to send your mail to your street address, the Internet knows how to send the right data to the right computer via an IP address.
1.A proxy server is basically a computer on the Internet with an IP address that your computer knows. When you send a Web request, your request reaches the proxy server first. The proxy server then sends the Web request on your behalf, collects the Web server's response, and forwards the Web page data to you so that you can see the page in your browser.
2. When a proxy server forwards your Web request, it can change the data you send and still provide you with the information you want to see. Proxy servers can change your IP address, so Web servers are not sure where you are in the world. It encrypts your data so it can't be read in transit. Finally, the proxy server can block access to certain web pages based on IP addresses.