This clear web site shows you if your PC is "leaking" your ip or dns, leaks that can reveal your identity. And suggests some remedies (plugin for chrome and a configuration modification for mozilla).
The first time I froze seeing my Internet Provider's dns on the screen while on a VPN.
I found it interesting: https:// ipleak.net
wow.. rly makes u think
What is this shit? Why are you not using Tor browser?