track ip addresses, phone numbers, etc

Check if you're behind a Proxy Server

By using a proxy server, your IP address will be hidden from websites and other web services that you use. Any web resource you access can gather personal information about you through your IP address. Anonymous proxy servers hide your IP address thereby saving you from vulnerabilities concerned with it.

Here are the variables sent by the server

VariablesValues
REMOTE_ADDR54.197.142.219
HTTP_X_FORWARDED_FOR54.197.142.219
HTTP_X_REAL_IP54.197.142.219

Setting up Web Proxies in Mozilla Firefox

Setting up Web Proxies in Internet Explorer