Top 3 Tools For Busting Through FirewallsCan't access a Web site thanks to employer or government censorship? Fortunately, there's a host of tools and techniques that can help you slip through the blockade. Here's an in-depth look at three of the best.
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Tor's makers provide a number of different software bundles to make Tor easy to work with. Among them is Torbutton, a Firefox add-on that makes it possible to connect to Tor through Firefox via a single mouseclick. Vidalia provides a graphical control panel for Tor, giving easy access to most of its commonly changed options. Other people have also found interesting ways to repackage Tor's functionality. The makers of the Ironkey encrypted USB drive package the Firefox browser with the drive, and include the ability to route Firefox through Tor via the Torbutton.
Tor's not without drawbacks, although they can be compensated for in varying degrees. For one, Tor doesn't (and in many ways, can't) prevent traffic entering and exiting the network from being monitored. This impacts anonymity indirectly. It isn't as easy to trace back the traffic from a given exit node, but any personally identifiable information sent through Tor can be spied on at either the entrance or exit. It's a little like using a pay phone to make a tip to the police when that phone's been bugged by criminals themselves.
Tor also doesn't by itself encrypt any traffic between an exit node and the final endpoint (for instance, an email server), so the only way to guarantee the contents of the data all the way through is to use end-to-end encryption, e.g., SSL. Tor's creators have tried to counterbalance all this by providing a FAQ about how not to compromise your anonymity.
Note that services published via the hidden service protocol don't have these problems, since they're confined to the Tor network -- but that's also their biggest drawback, since only Tor users can reach them.
Because Tor's creators have tried to strike a balance between protecting anonymity and making concessions to the rest of the Internet, a number of things built into Tor can work against the people who use it. Port 25 is blocked by default, for instance, so it's not possible to use Tor as an anonymous spam relay. Many peer-to-peer ports are also blocked, since using P2P software on Tor is considered a breach of etiquette, and hogs bandwidth needed by all.
Most importantly, Tor makes it possible for Web sites to set different access policies for Tor users vs. regular users by publishing lists of Tor nodes through a queryable service.
Developed by Bennett Haslelton of the anti-Internet-censorship site Peacefire.org, Circumventor works a little bit like Tor in that each machine running the Circumventor software is a node in a network.
Circumventor is most commonly used to get around the Web-blocking system in a workplace or school. The user installs Circumventor on an unblocked PC -- e.g., their own PC at home -- and then uses their home PC as a proxy. Since most blocking software works by blocking known Web sites and not random IP addresses, setting up a Circumventor instance ought to be a bit more effective than attempting to use a list of proxies that might already be blocked.
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