The_Great_Wall_of_China_at_Jinshanling-edit“If you open the window for fresh air, you have to expect some flies to blow in.” That was a favorite saying of Deng Xiaoping, who was referring to China’s economic reform that would ultimately transform the country. China’s decision to open its doors to foreign investment and western knowledge also let in the Internet and foreign ideologies. To keep those “flies” away, the Chinese government has implemented The Great Firewall of China—an Internet censorship and surveillance program.

I’m currently in China where access to social media (Twitter, Facebook), YouTube, Google, and many other sites is blocked. A number of media sites such as CNN and the New York Times are also blocked (you can test whether a website is blocked by using Update 5/25/16: if previous site is unavailable, try this one Not only that, the government surveillance encourages self censorship because Internet users believe they are being watched and could potentially suffer legal and economic consequences if they do not adhere to the government policy. The blockage of sites I take for granted at home means I cannot (easily) get to my g-mail, Twitter, and YouTube accounts. In addition to the inconvenience, such censorship is quite disturbing to someone accustomed to Western freedoms and beliefs.

The irony is that it’s possible to jump over the Great Firewall, and many people here do. How that’s accomplished requires an understanding of how the Great Firewall works, which is technically quite interesting. There are three main ways Internet access to certain sites is blocked. The first is IP Blocking, which works by blocking all access to a known IP address. For example, (a domain) maps to a known IP address; any attempt at connection is immediately disconnected (I would get messages saying that the server was unavailable, or the connection attempt would time out). The second way is called IP Address Misdirection, which does exactly what the name suggests. You might type in a url,, but the Firewall will send you to a fake address, The final method is called Data Filtering, in which an Internet search involving certain keywords (e.g., Tiananmen Square) will be intercepted and the content of the resulting URLs examined. If the URL is on the censored list, then access to that site is blocked.

Through the use of VPNs (virtual private networks) and other proxies, Chinese citizens and visitors like me can circumvent the firewall. These work by routing information through a server located elsewhere, for example, California. Your IP address is thus changed so that it appears you are located in the US, and your web activity is also encrypted. This change bypasses the various blocking procedures described above. However, Chinese authorities have begun identifying and blocking some of the more popular VPNs, making it a bit more difficult for the average person to jump the firewall. I found one that is currently working and is allowing me to (so far) post things on banned sites such as Twitter.

I knew about the firewall prior to this trip (having visited China before) and had assumed that Chinese viewers were unable to see my YouTube videos. Chinese colleagues also had mentioned to me that YouTube was not accessible in China. I now know that is not entirely true. In fact, a friend who is from China but lives in the US said that her friends back home told her about “The Scientist Videographer” and video tutorials. They were talking about using a GoPro to capture video, and her friends mentioned a tutorial showing how to shoot and edit a slow-motion video, which showed a hummingbird. After a moment’s confusion, she realized they were talking about someone she knew—me and my YouTube tutorials.

There is much, much more to this topic (see this NY Times article for an in-depth description) than I could cover in a brief post.

Image Credit: Wikipedia Creative Commons CC-BY-SA 3.0, uploaded by Brandmeister