Hack and / - Browse the Web without a Trace

by Kyle Rankin

Is privacy dead? When I think about how much information my computer and my gadgets output about me on a daily basis, it might as well be. My cellphone broadcasts my general whereabouts, and my Web browser is worse—every site I visit knows I was there, what I looked at, what browser and OS I use, and if I have an account on the site, it could know much more.

Even if you aren't paranoid (yet), you might want to browse the Web anonymously for many reasons. For one, your information, almost all of it, has value, and you might like to have some control over who has that information and who doesn't. Maybe you just want to post a comment to a blog without the owner knowing who you are. You even could have more serious reasons, such as whistle-blowing, political speech or research about sensitive issues such as rape, abuse or personal illness.

Whatever reason you have for anonymity, a piece of software called Tor provides a secure, easy-to-setup and easy-to-use Web anonymizer. If you are curious about how exactly Tor works, you can visit the official site at tor.eff.org, but in a nutshell, Tor installs and runs on your local machine. Once combined with a Web proxy, all of your traffic passes through an encrypted tunnel between three different Tor servers before it reaches the remote server. All that the remote site will know about you is that you came from a Tor node.

Tor works well on its own for anonymity, but anyone who has access to your machine can see that you have it installed. In some situations, even possession of anonymizing software might implicate you if you work in a company or live in a country where it is frowned upon. However, even in these cases, if you have a Knoppix disc, you quickly and easily can set up an anonymous Web browsing environment that will disappear once you reboot your computer. Because Knoppix boots and runs completely from the disc, any changes you make to it are stored in RAM and are erased once you reboot the machine.

First, you need a Knoppix disc. If you have a fast Internet connection, download a CD or DVD image from the official Knoppix site and then burn it to disc. Otherwise, look on the official Knoppix page for links to retailers who will ship you a Knoppix disc for a fee.

Next, boot your Knoppix disc. Knoppix should attempt to get on the network automatically, but if it doesn't, click K→Knoppix→Network/Internet for network configuration options. Knoppix has a sophisticated system that allows you to write to all areas of the filesystem as though it were installed on a hard drive. Because of this, you actually can install Tor on Knoppix according to the official directions on the Tor site. First, click K→Knoppix→Utilities→Manager software in Knoppix to start Knoppix's package manager. Then, click Reload to get the latest list of packages, search for the privoxy and tor packages, and select them for installation (or, if you want a shortcut, simply open a terminal and type sudo apt-get update && sudo apt-get install tor privoxy).

Now Tor will be set up and running, but Privoxy still needs a bit of extra configuration to use Tor. Open /etc/privoxy/config in a text editor, and add this line to the top of the file (don't forget the trailing dot):

forward-socks4a / .

After that, find any lines that look like the following and comment them out with a #:

logfile logfile
jarfile jarfile

Finally, open a terminal and type:

sudo /etc/init.d/privoxy restart

And, Privoxy will be ready to use.

Although you could configure Iceweasel (Firefox's name on Knoppix) by hand to use Privoxy, there is a nice plugin created just for Tor. Open Iceweasel and go to https://addons.mozilla.org/firefox/2275 to install the Torbutton plugin. Once you install the plugin and restart Iceweasel, a button at the bottom right of Iceweasel will appear that says either “Tor Disabled” or “Tor Enabled”. Simply click the button to toggle the state, and the plugin will take care of the rest.

From here, you can browse the Web anonymously. If you have never used Tor before, it's worth noting that you might see a slowdown in performance, as your traffic does need to be encrypted and pass through three extra servers. Also, certain sites, such as Google, may appear in their German or Japanese versions, depending on which Tor node you exit through. Once you are finished, shut down the machine, and all traces of Tor, Privoxy and your browsing history will be erased.


Official Tor Site: tor.eff.org

Official Knoppix Site: www.knoppix.org

Kyle Rankin is a Senior Systems Administrator in the San Francisco Bay Area and the author of a number of books, including Knoppix Hacks and Ubuntu Hacks for O'Reilly Media. He is currently the president of the North Bay Linux Users' Group.

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