A University of California researcher has developed a technique to uniquely identify a PC anywhere on the internet, even if it is hidden behind a firewall or shares its IP address with other computers:
How to track a PC anywhere it connects to the Net: ZDNet Australia: News: Security:
"Anonymous Internet access is now a thing of the past. A doctoral student at the University of California has conclusively fingerprinted computer hardware remotely, allowing it to be tracked wherever it is on the Internet.
In a paper on his research, primary author and Ph.D. student Tadayoshi Kohno said: 'There are now a number of powerful techniques for remote operating system fingerprinting, that is, remotely determining the operating systems of devices on the Internet. We push this idea further and introduce the notion of remote physical device fingerprinting ... without the fingerprinted device's known cooperation.' "
Thanks to Privacy Digest for the pointer to this story.