China’s “Great Firewall” (GFW), officially the Golden Shield Project (金盾工程) of the Ministry of Public Security, is both clever and stupid, subtle and blunt.

As with any Internet filtering system, there’s only two methods to block bad stuff: keep a list of “bad sites” and prevent access, or look at the content live and figure out whether it’s good or bad on the fly. GFW uses both.

Al Gore was mocked for calling the Internet the “Information Superhighway”, but the analogy works. Like the road network, a maze of suburban streets leads to relatively few freeways, all administered by a myriad of local authorities.

When your computer requests a website, imagine a truck driving out your front gate. The driver knows the site’s name but not how to get there. Normally, you’ll get directions.

“Amnesty International? Sure, that’s 78.136.0.19,” says the domain name system (DNS).

“78.136.0.19? Go via Telstra, ask again once you’re in San Jose,” says your ISP’s router. In SJ, you’re told to go to New York and so on to Amnesty’s London office.

In China, though, your driver only gets blank looks.

“Amnesty? Never heard of it.”

“78.136.0.19? No, no such place.”

With relatively few links connecting China to the world, this block is easy. Unlike Senator Conroy’s porn filters, GFW doesn’t have to worry about collateral damage. It blindly blocks entire sites, as well every site sharing the same Internet address — not only Amnesty, but everyone in that office tower.

The GFW also looks at content, and here’s the true subtlety.

Researchers at the ConceptDoppler project have found that it can disrupt Internet traffic within China that even mentions touchy subjects. Imagine your truck encountering random checkpoints. If it contains banned concepts like “news blackout” (新闻封) or “gerontocracy” (老人政治) your delivery is simply burned, never to be seen again.

ConceptDoppler says the banned words still get through 28% of the time, and the blocking can’t keep up with heavy Internet traffic. But even partial blocking encourages self-censorship through the perception that you’re being watched. Perhaps that’s even more effective because it discourages offline conversation too.

Getting around GFW is easy enough for geeks — though perhaps beyond the skills of average Internet users like sports journalists. Wikipedia lists the techniques, and Reporters Without Borders has a handbook.

Using proxies is like first sending your truck to a benign destination so it gets those helpful directions. Once there, the package is opened and the secret instructions inside forward your message to the real destination. To avoid content filtering, just speak in code. Learn to say “duck-breeding club” rather than “student dissident meeting”.

Further Reading

I gathered these links during my research for this story:

1. The Connection Has Been Reset: China’s Great Firewall is crude, slapdash, and surprisingly easy to breach (Atlantic Monthly).
2. China’s All-Seeing Eye, Naomi Klein (Rolling Stone).
3. Empirical Analysis of Internet Filtering in China, from Harvard Law School.
4. Real-time test to see if your website is currently being blocked by the Great Firewall of China.
5. Behind the Great Firewall, Net Nannies work overtime for companies, suggests self-censorship more the norm.
6. fuzheado’s ongoing Great Firewall coverage on Twitter.

And a Crikey commenter called Justin added these, none of which I’ve checked out personally.

1. HOWTO bypass Internet Censorship, a tutorial on getting around filters and blocked ports
2. Proxy.org — The Proxy Authority
3. Vtunnel.com is here to help you beat internet filtering!
4. Ninja Proxy | Fast, free, anonymous web browsing with NinjaProxy.com
5. Your Freedom
6. Free Proxies: Freeproxies.org hosts the best cgi proxy servers on the web, for free.
7. Free Anonymous Surfing, Free Surfing through a Proxy (thefreecountry.com)
8. Stunnel.org