If you visit a site that exploits the WebRTC vulnerability including whatismyipaddress.com it may show "Local IP Address" which would be the real IP of your machine.
The vulnerability works on Windows and Linux machines (contrary to false information on the web which claims it only affects Windows).
The above works and happens even if you are using a proxy or VPNaccount like ProVPNAccounts.com
It is easy........
First of all, the iPhone is crippled in many ways, but most of my complaints about functionality have been addressed through the jailbreak, Ican run apps in the background of my choosing, I can install a terminal, acccess my phone through SSH and SCP and so much more.
It even addresses the 15 minute e-mail problem, I installed a program called "PushMod" and now set the checking time to just 1 minute.
Apple should really thank the developers for this gift, it ma........