The Great Firewall of China refers to legislative actions and technologies put in place by the People’s Republic of China to domestically regulate the internet. It is a nation-wide firewall composed of multiple layers and managed by government IT personnel that allows China to control content through the largest system of censorship in the world. Sites blocked by the Great Firewall include Twitter, Facebook, the New York Times, and Google and its services, such as YouTube.
The Great Firewall is a national effort to protect Chinese infrastructure from cyberattacks. It was formerly a part of the Golden Shield Project, but since 2013, it’s been operated by the Cyberspace Administration of China, the central internet regulator, censor, oversight, and control agency for the People’s Republic of China.
How does the Great Firewall of China work?
The firewall uses IP address blocking, DNS cache poisoning, analyzing and filtering of URLs, packet inspection and filtering, and resetting connections to redirect IP requests if they are for blocked websites or keywords. In China, most Virtual Private Network (VPN) providers are also blocked, and citizens must use a government-approved option, which doesn’t give them much flexibility to use the internet.
Websites that are blocked by the Great Firewall appear as though they are experiencing technical issues rather than communicating that the site has been blocked. Technical issue messages that a blocked site may show include a 404 Page Not Found error, the connection needs to be reset, or the page has timed out.
There are ways to circumvent censorship using proxy nodes and encrypting data. Methods for evading the Great Firewall are as follows:
- Using free programs such as Freegate, Ultrasurf, Psiphon, and Lantern to circumvent the firewall using multiple open proxies
- Using a proxy server
- Using a VPN
- Using Tor, a free and open source software used for anonymous communication by directing traffic through an overlay network that conceals a user’s location and usage from anyone conducting network surveillance or traffic analysis.
- Using I2P, an anonymous network layer similar to Tor that allows for censorship-resistant communication. Since I2P is less popular than Tor, it faces less blocking attempts.
