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I've heard mention that there's tools for linux that will obscure the "fingerprint" your machine provides to snooping parties on the internet-- however I've been unable to find any mention in the repos or any writeups.

Can anyone provide any info on a tool to obscure the TCP/IP fingerprint in Ubuntu?

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I'm guessing you're talking more about OS and open service identification than about hiding your browser traffic, correct? Like nmap used to do? – Abe Voelker Dec 31 '11 at 1:28

It all depends on what you mean by "fingerprint".

There's the fingerprint of the Internet services your machine provides (which port, which software, which version, if available), if it's connected to the Internet (remember, if you're connected to the Internet, the Internet is connected to you). You can minimize the size of this fingerprint by being behind a well-administered firewall, reducing the number of services your machine runs, running services on non-standard ports, editing version strings, etc, etc.

Then there's the fingerprint of the IP address your ISP has assigned you. TOR (see previous answer) can help with that, but with a sufficiently detailed examination, one might be able to see a 47.853GB download of a forbidden document from some evil website to a TOR node, AND one might be able to see a 47.853GB encrypted file from some TOR nodes to your IP, and draw conclusions.

Then there's the fingerprint your browser presents to the sites you visit (via TOR or not). The PanoptiClick project of the Electronic Frontier Foundation to see how unique your browser configuration and add-ons are.

Then there are actual fingerprints - wear thick gloves.

First, consider what you want to secure, then from whom (well, really, do a Threat and Risk Assessment), and figure out how much effort/time/money it will take to secure it. Is your "fingerprint" your machine provides to snooping parties on the internet, really the highest risk?

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You might be referring to Tor, which is a way to use the Internet anonymously. The website for information about Tor is here. The site describes Tor:

"Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy."

It was originally developed for use by the U.S. Navy, but now is used by many other agencies, businesses, and individuals.

The method is described in this way:

"The idea is similar to using a twisty, hard-to-follow route in order to throw off somebody who is tailing you — and then periodically erasing your footprints. Instead of taking a direct route from source to destination, data packets on the Tor network take a random pathway through several relays that cover your tracks so no observer at any single point can tell where the data came from or where it's going."

Of course, there is much more information on that page, and if it is of interest, you ought to read up about it; there is a lot to learn and understand. There are also links to download Tor and set it up at the site.

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If you change your TTL nmap won't recognize your OS, as reported here. You can do it with the following command:

echo "net.ipv4.ip_default_ttl = 64" >> /etc/sysctl.conf
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