Whether related to the rumored murder charges against the wife of former Communist elite Bo Xilai or the earthquakes in Indonesia and Mexico over the last day, one thing is for sure: Internet connections to websites outside of China were intermittently not available to many users in China today.

The problems were first noticed about 10:00 on April 12 in Beijing. Local Chinese websites like Sohu.com and Sina.com appeared fine and seemed to have no lost latency. However, visiting other websites on servers outside of China, such as Yahoo.com, Microsoft.com, or Gmail.com, proved difficult, as they were not totally available. Connections through China Unicom did not appear completely closed, but they did appear greatly diminished. If the China Unicom bandwidth was a highway, it would be like reducing the highway from a 20-lane high-speed thoroughfare down to a cobblestone pathway.

Guan Peng, deputy general manager of China’s Yanhuang Network, posted a message on Weibo saying that a number of domain name servers have been blocked, and websites using overseas hosts cannot be accessed.

Digging deeper, the problem appeared to mostly affect China Unicom Internet users. Users of China Mobile’s services reportedly have no problem viewing either domestic or foreign websites in China. Likewise, services like Feedburner, Twitter.com, Facebook.com and WordPress.com, which have traditionally been blocked in China, are of course still not available to Chinese users.

Too add another layer to the cause of problem, Skype appears to work fine in China, even if using the version of the product that is not in partnership with Chinese Internet firm Tom.com. Because Skype uses different ports than are used for Web surfing, the problem could be one solely related to a technical glitch.

The earthquakes might also be the cause of the problem. Indonesia had a massive earthquake yesterday, followed by a 7.0 earthquake in Mexico today. Multiple times over the last 15 years, earthquakes in and around the Pacific Ocean have ruptured cables that deliver Internet connections between Asia and North America. It takes weeks sometimes to fix these problems, and in recent years businesses and users in China have been starved of important information on foreign Internet websites while these cables were fixed.

Many foreign websites over the last day have reported the jailing of the wife of former Chongqing city chief Bo Xilai on apparent murder charges related to the death of a Briton. In the past decade, websites from foreign news media like CNN, NYTimes.com, and BBC have been sporadically blocked. Plus, two years ago the Chinese government closed off entirely the Internet access to users in the northwest Chinese province of Xinjiang. So there have been precedents for the Chinese government to sever Internet connectivity.

As of this moment, three hours after the first reported outage, most foreign websites are available again.