If you want something done right, you have to do it yourself.
This is why I’ve implemented my own What is your IP address and proxy server tool.
In addition to IP address, I’ve also built a What are your HTTP headers tool.
The IP address tool attempts to detect and expose a proxy server, if one is in use, and show the address behind the proxy, if known, as well as the public IP address.
And the HTTP headers tool shows all of the HTTP headers sent on that request, and if you are experimenting with Bad Behavior, you’ll find this an invaluable tool.