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China Blocks MIT Web Addresses

By Keith J. Winstein


The Chinese government has been blocking access to the “” Internet domain since late August, according to several Chinese reports and an examination by The Tech.

It is unclear why China has imposed the block, which includes access to OpenCourseWare and all MIT Web sites, but not e-mail sent to MIT students and faculty through Web-based services such as Hotmail.

A spokesperson for the Chinese embassy in Washington, who asked that his name not be used, confirmed that China was blocking access to MIT Web sites, but said neither he nor his colleagues in China knew why it was imposed.

“I don’t think that this kind of Web site should be blocked,” he said, indicating that he did not think China would block access to an “edu” educational domain.

DNS servers give bad directions

The method of blocking involves misdirecting Chinese surfers looking for “” sites, by having domain name servers in China give intentionally wrong answers. Domain name servers translate the computer names that users type in, such as “,” into the numeric addresses by which computers on the Internet are known.

When examined last week, Chinese domain name servers, including those run by the Chinese government, repeatedly gave out an incorrect answer for any query containing the text “”

The incorrect answer is the same address given, also incorrectly, for sites such as “,” which discusses the Falun Gong spiritual movement banned by Chinese authorities.

OCW sees little traffic from China

“It disappoints us when a large segment of the population can’t benefit from [our work],” said Anne H. Margulies, the executive director of OpenCourseWare, MIT’s program to post homework, tests, and other teaching material for its classes on the Internet at .

“When we originally opened our site to the public on Sept. 30, we watched the traffic,” she said. “We could see that we were initially getting traffic from China.”

“Then we got a handful of messages from individuals in China,” Margulies said. “They e-mailed us that they could no longer get to our site. That went on for a couple of days. Then we checked our stats and saw that there was, indeed, no traffic from China.”

Margulies said that “oftentimes, the Chinese find workarounds” to blocks by, for instance, accessing sites directly by numeric address, but “that’s obviously a vast minority,” she said.

Block affects MIT-China program

Sean Gilbert, coordinator of the MIT-China program, said the block has “become an inconvenience, but it hasn’t hurt us at all.”

MIT students studying in China through the program have found that “they’re not able to access all their MIT e-mail or the MIT Web site,” he said. These students have adapted by forwarding their mail to Hotmail or other non-MIT e-mail services.

In the future, Gilbert said, the program is looking into using MIT’s OpenCourseWare site to teach in China, but “if you can’t access the MIT Web site, then we won’t be able to do it,” he said.

“Some people think there’s a formal strategy in China to block these sites,” Gilbert said. “Other people think it’s kind of haphazard.”

DNS block one of several methods

Benjamin G. Edelman, a Harvard Law School student researching China’s filtering behavior, said the sort of block used on the “” domain -- giving an incorrect address -- was one method China uses to block Web sites, but “not the primary method.”

China’s “primary method is to configure routers to discard requests destined for prohibited Web servers,” Edelman said. China also filters e-mail and requests in URLs “for prohibited terms,” he said. For instance, Chinese Internet users may access the Google search engine, but are prohibited from searching for Falun Gong-related keywords.

With Professor Jonathan Zittrain of Harvard Law School, Edelman has created a real-time tester of China’s Internet blocks, at . However, when tried this week, the tester appeared to be malfunctioning, erroneously reporting all sites as “accessible.”