Communications of the ACM
How Nations Block Facebook
Last month, Facebook came close to signing up its 700 millionth user. But it is no “friend” of several governments—including China, Iran, and Syria—which are doing their best to block the Web site and other social media, like Twitter and YouTube, from their citizens.
A joint project known as the OpenNet Initiative compiles a fairly up-to-date list of these governments.
While banning these sites may seem like a monumentally difficult task, it is actually rather simple to keep them out of the hands of the average user, especially if you have control of Internet access in your country, as some governments do, says Earl Zmijewski, VP and general manager of Renesys, which monitors the global Internet.
“For instance, in China, there are a limited number of providers, the largest of which is China Telecom,” he explains. “The government simply instructs them as to what they will or won’t allow and then it’s easy for the provider to block the IP address associated with, say, Facebook.”
Or the ISP can use a process known as DNS cache poisoning which re-directs users trying to access Facebook to different IP addresses.
Or the provider can use deep packet inspection to block certain terms. “We know from academic papers that in China,” says Zmijewski, “you can go to Wikipedia.com, for example, but if you try to look up, say, ‘the Dalai Lama,’ that phrase will be observed as it passes through what’s known as The Great Firewall, which is not just one box but is their mechanism for control. In that case, your connection will be torn down and you’ll never get the page.”
Facebook was available in China until year-end 2010 if you knew how to access it through its IP address, says Zmijewski. However, it is no longer accessible in China, especially since the beginning of the revolutionary movements in the Middle East, he says.
Zmijewski recalls that Egypt had been trying to block social media prior to President Mubarak’s departure. “They weren’t very sophisticated in the way they attempted it so, in the end, they just turned the Internet off which is a sure way to block everything—a rather blunt instrument but effective.”
But, despite all the efforts of repressive governments, tech-savvy users are aware that workarounds exist, the most effective being The Tor Project, a volunteer network of servers, many located at universities around the globe.
“When there’s no other way to access a site like Facebook, your only choice is turning to an indirect, cooperating third-party who encrypts the data and then uses its own servers to deliver it,” says Zmijewski. “It’s very slow but, when you’re in a bind, it’s effective.”
However, governments are also becoming more effective at blocking sites. “For the Chinese government, blocking social media has become a moving target that they are becoming better and better at hitting,” says Zmijewski.
Currently, the Electronic Frontier Foundation (EFF) is sponsoring an “EFF Tor Challenge” to encourage growth of the Tor network.
“The more organizations that get involved in Tor, the faster the network works, and the more secure and robust it becomes,” says Eva Galperin, an international activist at the EFF, a digital civil liberties organization.
Meanwhile, at the same time, the EFF is fighting another battle, this one much closer to home. According to Galperin, the technology that governments use to thwart access to social media is mostly manufactured in the U.S. and Canada.
“These companies sell their software to foreign governments for the explicit purpose of reading Internet traffic,” she says.
As part of the Global Network Initiative, the EFF is just one of 27 non-profit organizations, human rights organizations, and technology companies—mostly located in Silicon Valley—that have been active in helping to publicize the software vendors’ actions.
“Our only weapon has been to shame them,” says Galperin. “Other than that, we don’t have a whole lot of leverage.”
Paul Hyman was editor-in-chief of several hi-tech publications at CMP Media, including Electronic Buyers’ News.
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