How It Works: Great Firewall of China


Anyone who have been to China have experienced this: access to certain foreign websites such as Google and Youtube are either blocked or intentionally slowed down. This presents a huge obstacle for many foreign enterprises seeking to gain a foothold in China. The Great Firewall of China is part of the People’s Republic of China censorship regime to regulate the Internet and ‘protect’ its citizen, or so they say.

The Firewall has seen several iterations over the decades and has become far more complex and sophisticated than one can imagine. Nonetheless, China’s Great Firewall seems to be getting only stronger with reinforcements such as Artificial Technology (A.I) to improve its existing security measures. The idea to connect to the outside world economically but remained closed off from Western ideologies is something once unfathomed of, but now a reality.

The recent cryptocurrency boom and subsequent ban of cryptocurrency trading by the Chinese authorities was a dominant display of the Firewall capabilities, with many foreign cryptocurrency websites blocked and local crypto-exchanges forced to relocate overseas. Perhaps the most news-worthy (and funny) censorship is the blocking of Winnie the Pooh in China after critics depicted Xi Jinping, the current President of the People’s Republic of China to the fun and loving teddy bear. The uncanny resemblance has forced the Chinese authorities to remove all Winnie the Pooh related images from Chinese websites.

A comparison of Xi Jinping and Winnie the Pooh

A Brief History of the Great Firewall of China

Back in the 1980s, Deng Xiaoping, the paramount leader who brought forth economic reforms through the creation of a market economy was famously noted for saying: “If you open the window for fresh air, some flies will be blown in” (打开窗户,新鲜空气会飞进来,苍蝇也会飞竟来). What this meant was that while opening China to the world will bring in economic development and progress, it will inevitability bring in unwanted Western beliefs and ideologies that the Chinese government view as ‘corrupted’.

First introduced to China in 1989 in the form of small-scale pilot projects, the Internet was made available to the entire nation in 1994. As of Jan 2018, the total online population in China peaked at 772 million. The Chinese government knew that opening up the Internet was necessary for China to grow economically but feared for the repercussions of opening up the nation to Western ideologies.

In 1998, the Golden Shield Project (a.k.a National Public Security Work Informational Project) was initiated. Several projects were planned under the Golden Shield, including security management information system, criminal system as well as the all mighty Great Firewall of China. The Golden Shield Project was initially implemented to enhance network security, but soon expanded to include censorship and surveillance. The project enabled maximum control of the Internet by the Chinese Communist Party (CCP).

Ironically, foreign companies such as Nortel Networks and Cisco Systems were hired to oversee the development of these projects. These companies provided the necessary hardware and software to build the largest security network system in the world, a move that sparked controversy among the global community for its contributions to human rights violations in China.

How It Works

All Internet services providers in China are licensed and controlled by the Ministry of Industry and Information Technology, meaning that every content in and out of China can be monitored and manipulated by the Chinese authorities. Under the Great Firewall, several methods were employed to enable a catch-all measure.

  1. URL Filtering: Web traffic are filtered based on a URL filtering database, denying access based on the list of websites in the database. Websites containing sensitive keywords such as “Tiananmen” are blocked or selectively filtered.
  2. DNS Poisoning: When users connect to websites, computers will contact the DNS server and request for the IP address. The Firewall works to ‘poisons’ the DNS responses, returning corrupt addresses and making the websites inaccessible at all.
  3. Self-Censorship: According to laws and regulations, Chinese firms are responsible for their content and violations will lead to harsh penalties from fines to shutdowns. Henceforth, many large enterprises set up enforcements teams to regulate and ensure that their platforms do not contain prohibited topics.
  4. Manual enforcement: Hundreds of thousands of civilian workers are employed all over China to enforce censorship and filter out ‘harmful’ content considered detrimental to the progess of China. These censor workers contracted by the authorities monitor online content, informing any potential violations and having officials to make on-site investigations. Some sites provide back-end access to allow censor workers to edit content directly. However, recent advancement in A.I technology has allowed the monitoring processes to be automated.
  5. Blocking VPNs: Virtual Private Network (VPNs) are a common way to circumvent the Great Firewall. Termed “ Climbing Over the Wall” (翻墙, Fan Qiang) within the Chinese community, VPNs are the cheapest and most effective method to work around the Great Firewall, albeit it is not fool-proof. During sensitive events such as the death of Nobel Peace Prize winner Liu Xiaobo in July 2017 or the 19th National Congress of the Communist Party of China in October 2017, VPNs were blocked, a move that crippled many foreign enterprises working in China. However, the Great Firewall was loosened during the Beijing Olympics in 2008, allowing foreign media and players to access most of the blocked websites. The Firewall works by identifies “VPN-looking” traffic and kills off the connection, preventing it from connecting to foreign servers. Reports to implement a blanket ban on VPNs in February 2018 proved to be only rumours.

Foreign social network sites like Youtube and Twitter are blocked, causing Chinese citizens to adopt local versions of it such as Youku and Sina Weibo where censorship and propaganda can be easily reinforced.

An infographic of the platforms used by the Chinese locals.

The Good and the Bad

Indeed, the Firewall was very effective in preventing the influx of Western beliefs. The communist and dictatorship ideology is still very much alive in today’s China, albeit not so in-grained among the millennials. In rural and unstable regions such as Xinjiang, online media are heavily scrutinized compared to developed cities such as Shanghai to prevent potential conflict brought by the Internet. Essentially, the government controls what users want to see, impeding freedom of speech and violating human rights in the name of Communism.

Besides political agenda, the Great Firewall of China also served an economic purpose. By deterring foreign enterprises, China was able to protect and nurture domestic companies by having the whole pie to themselves. This was one of the reason for the rise of Chinese giants such as Baidu, Alibaba and Tencent, or BAT. Foreign expanding to China would have to abide to domestic regulations, including what or what not to post one the Internet.

The Great Firewall of China did a great job in sealing up the nation, to the extent that it had bred ignorance among its citizens to the outside world. Many Chinese citizens are well-aware of the Firewall, and are used to living within it. Many of their online activity needs are satisfied by the plethora of Made-In-China social media platforms and copy-cat apps. Most of the large-scale media enterprises are either state-owned or closely monitored by the authorities. International news is selectively edited and filtered to ensure that users will only see what the authorities wants the nation to see. In the recent 2018 World Press Freedom Index surveyed by Reporters Without Border, China was ranked Ranked 176th out of the surveyed 180 countries.

The Firewall have also dealt a fair amount of collateral damage in the areas of science and innovation. Researchers in China have been severely hindered by the inability to access overseas scholarly work. For decades, the Firewall have locked local companies and students nationwide from connecting with the outside world, limiting the exchange of ideas and knowledge. To curb this, the Chinese government gives out generous subsidies to companies expanding abroad as well as scholarships to students studying overseas. It has always been seen as an attempt to import knowledge back to China, a move that nations including U.S. and E.U has condemned by preventing Chinese companies from setting up abroad and disallowing Chinese-led acquisitions.

To the typical Chinese local, the Great Firewall is inconsequential. To the intellectual Chinese, the Firewall is a huge burden. Whether the Firewall did more damage than good to China is up to debate.

Firewall? China is not Alone

In the early days of the Internet, it was seen as a breakthrough technology that could unite the world together. It brought about incredible convenience and empowered every individual with access to it. It has also allowed freedom of speech by keeping it online and decentralized. However, for China, it was a tool that encouraged diversity and democracy, something that the Chinese authorities have sought to prevented. While we will not see the move towards a Chinese intranet, we will expect to see a tightening of controls with the strengthening of Xi Jinping’s dictatorship.

Recent developments have pointed to the fact that China is not alone. Increasingly, we are seeing other nations following the likes of China in imposing their own firewall. Russia has turned to China for help to step up its censorship capabilities. Countries like US and UK have also built firewall capabilities and now block blacklisted websites. While these countries have good intentions, we have no knowledge of how these capabilities are harnessed for other undisclosed purposes, from silencing dissent to preventing unwanted propaganda.

While the Internet is still serving its intended purpose to be an online universe of knowledge and as a tool for communication, it has also became a battleground for the spreading of ideologies. The Firewall is the first of the many defenses nations have set up and it is without a doubt that the Internet will be soon be equipped as a weapon of mass destruction.


Hi all! I’m a freelance writer based in Singapore. I write about the latest tech happenings in the various industries as well as commentary on China. I also welcome any job opportunities that arises. Email me at

All donations will go towards paying off my student loan debt !!! ERC-20 token: 0xC70A50348efa21caD9046407d168e656bD11a0f0

Adventurer, Hustler, Tech enthusiast