HONG KONG — China appears to have reinforced its Internet firewall in recent days, blocking some of the leading services that allow people on the mainland to access forbidden sites like Twitter, Facebook and YouTube.
International business transactions also are being affected, Internet analysts said. The New York Times Web site remains 100 percent blocked on the mainland, along with the Chinese-language edition of The Times and Rendezvous.
At least three foreign companies — Astrill, WiTopia and StrongVPN — have apologized to customers whose virtual private networks, or VPNs, have been slowed or disabled. VPNs are used to circumvent the Communist government’s firewall. The companies, meanwhile, were suggesting some work-arounds.
The daily newspaper Global Times, affiliated with the Communist Party, acknowledged the firewall had been “upgraded,” but it also warned that foreign providers of VPN services were operating illegally.
China blocks online searches of politically sensitive terms, smothers embarrassing news events, blocks online messages from dissidents and simply deletes any microblog posts that it dislikes.
The firewall also blocks countless Web sites that are openly available to users elsewhere around the world — from pornography sites and commercial come-ons to news reporting, political activism and religious proselytizing. Users on the mainland thus have to use VPNs to reach the banned sites.
Liu Xiao Ming, the Chinese ambassador to Britain, told the BBC on Friday that there was “a misconception about the Internet and development in China.”
“In fact, the Chinese are very much open in terms of the Internet,” he said, quoted in an article in The South China Morning Post. “In fact, we have the most number of Internet users in China today.”
An estimated 600 million Chinese have access to the Internet.
Foreign businesses also use VPNs not only to safeguard their transactions but also to keep government censors and rival companies from seeing their corporate communications.
Global Times quoted an anonymous executive at a foreign technology company operating in China who said the lack of a VPN would damage the firm’s operations.
Josh Ong, China editor of the tech monitoring site The Next Web, said in an interview with the Voice of America that international companies were reporting disruptions in their corporate VPN services.
“A lot of companies have a general policy that they must use their own proxy network in order to transfer data, especially into and out of China,” Mr. Ong said. “So you are looking at banks or e-commerce companies, anyone who is transferring very sensitive information, a lot of them use corporate VPNs.”
Mr. Ong suggested that the tightening of the firewall could be tied to the recent leadership change in the Chinese Communist Party.
“It is certainly possible that some of it is just a general flexing of might, kind of coming in with a strong arm to really show who’s in control,” he said. “But there is definitely something intentional happening when these VPN services are being restricted.”
As Bill Bishop wrote recently on DealBook, China’s management of the Internet “has not been encouraging for those who want to believe the leadership will push reforms.”
“I have lived in Beijing since 2005, and these have been the most draconian few days of Internet restrictions I have experienced,” he said last month.
“Indiscriminate blocking of major parts of the global Internet is not going to help China in its quest to internationalize the renminbi and make it a reserve currency,” Bill said. “Internet controls at the level of the last few days may also deter foreign firms from moving their regional headquarters to China.”
Barbara Demick of The Los Angeles Times bureau in Beijing offered this cautionary tweet:
My colleagues Sharon LaFraniere and David Barboza wrote about similar concerns over China’s Internet censorship last year, and they spoke to Duncan Clark, chairman of BDA China, an investment and strategy consultancy based in Beijing.
“It has been double the guard, and double the guard, and you never hear proclamations about things being relaxed,” said Mr. Clark, a 17-year resident of China. “We have never seen this level of control in the time I have been here, and I have been here since the beginning of the Internet.”