Information from any site comes to the user via a known route: site server -> ISP -> computer. The Beijing government has introduced a fourth component that lies between ISP and user: a security server. It automatically controls the information that goes to the user.
It should be noted that the firewall does not have integrity: in different parts of the country sites are blocked independently of each other and it does not happen at the same time. More than that — only a portion of users get a “friendly” message that the information on the page has been blocked. Sometimes access is denied, creating the visibility of a non-working site.
The list of forbidden topics is huge: in particular, on the Chinese Internet it is forbidden to use the words “communism”, “Tibet”, “Taiwan” and “independence” in one text. In addition, “incorrect” descriptions of historical events are prohibited. In opposition, active users have formed a whole slang that allows to mask objectionable discussions: for example, the word “censorship” is replaced with “river crab”.
Obviously, it’s not for the giants of the internet market. In China, websites such as Google, Wikipedia and Youtube (under the pretext of pornographic or political content) are regularly “shut down”, and local counterparts are planted instead. In response, Google openly tells users “keywords” that are intercepted by a firewall and recommends that they be avoided. But Yahoo’s search engine gave up without a fight: accepted the terms of the authorities and put filters directly on the servers.
However, the defense is not so impenetrable. Chinese Internet is filled with articles “Open Youtube in 10 steps” or “How to search Wikipedia”, and at great desire you can purchase inexpensive equipment that allows “Golden Shield” to bypass. The only problem is that it is punishable — and punishable in public, in the edification of others.