Disconnected: web offline for two hours

Access to cyberspace was hindered for more than two hours on the mainland yesterday, as virtually all foreign websites were inaccessible - with no official explanation.

At the same time, internet users outside the mainland, including in Hong Kong, reported they couldn't access mainland-based websites.

Some mainland internet analysts speculated the problem was probably due to a serious hardware malfunction afflicting major internet service providers.

Connections to websites in overseas regions or countries, including Hong Kong, Japan, South Korea, the United States, the Netherlands, Singapore and Australia were cut off at around 10.40am, according to a report on Ccidnet.com, a mainland-based IT industry portal.

Most mainland internet users were relieved as web access was gradually restored to normal after about 1pm, but some remained sceptical of the cause, as neither service providers nor the government offered an explanation.

In an attempt to determine the source of the problem, network engineers for Ccidnet.com tried to connect to a server in the US using a China Telecom server in Xuzhou, Jiangsu, the site's report said. But despite repeated attempts, not a single packet of data could be sent or received.

Using specialised software, the engineers traced the problem to a bottleneck involving two routers in Shanghai, a major hub that connects mainland and overseas cables. Data traffic at the juncture was found to have become suddenly congested.

The website engineers also reported that, during the incident, some domestic websites were affected. Sites such as Networkbench.com took more than six times longer to load than usual.

The abrupt blackout and lack of any explanation prompted widespread speculation among mainland internet users.

However, William Long, an IT expert and internet-freedom blogger based in Shenzhen, wrote that the problem seemed technical rather than political.

He said he had tried to establish a connection using other internet protocols, but his efforts were in vain.

'This problem is caused by issues in China's core network infrastructure,' he concluded.

A spokeswoman for China Telecom could not be reached for comment yesterday. And the administrative office of China Unicom, another major internet service provider, did not respond to inquiries.

Beijing recently stepped up its controls over online speech, especially on wildly popular microblogs, following the fall from grace by Chongqing's Communist Party boss, Bo Xilai, and after unfounded rumours of an alleged coup within the party last month.

Liu Zhengrong, a senior official with the mainland's internet watchdog, told China News Service yesterday they had deleted more than 200,000 'rumours' and shut down 42 websites since the middle of last month. 'Some overseas users created and spread rumours on the mainland's microblog websites. Cyberspace is very complicated,' he was quoted by the agency as saying.

Mainland internet users totalled half a billon last year, according to official statistics. And more than 350 million people accessed the internet via their mobiles.