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What is it ?

IPFuck is a firefox addon created to simulate the use of a proxy. With this addon installed and enabled, and if a lot of us use it, there will no longer be any mean to know who is using a real IP, who isn't and who was charged doing something he didn't... Basicaly : we all become anonymous !

This addon is a "proof of concept" to show anyone who isn't already aware that IP address has become obsolete and that no one should use an IP address as an evidence anymore. This plugin is just one of many ways to spoof an IP address and these spoofing could lead to outrageous accusation of innocents.

How does it work ?

You can imagine that if I could just overwrite any existing information about your IP address I would have done so (or somebody else would have a while back ago)...

But it's actually a little more tricky : when sending a request to a server you will provide several information about your IP address : three of them come from the Application Layer and the last one comes from the Transport Layer. This last one I can't modify : you wouldn't get the answer to your request if that was done. But the three others can be overwritten without any consequence to your browsing...

These three headers were created to provide information on the real IP of a person surfing through a proxy server. So when you enable IPFuck, the websites you are visiting will believe that your real IP is a proxy server and (if the website was done correctly) focus on the false IP you are sending...

A lot of websites try and figure out who is hidding behind a proxy server. And if you don't believe me (I won't mind), just check out this google search request : get real ip address php. Most of the snipplets given here will check HTTP headers (the one we overwrite) before the Transport Layer information ('REMOTE_ADDR').

What if ?

What if this addon spreads and everyone changes his website code to only check for the Transport Layer information ? Well then, they will lose any information on anyone hidding behind a proxy...

There is just no way to know anymore who's who and if the IP you're detecting as connected to your website is a real one or a spoofed / behind a proxy one !