China is the owner of the largest and most-complex country-wide firewall on earth.
Getting past the firewall, and being able to access the thousands (or even millions) of websites that are blocked may be tricky, but it can ultimately be done.
Before we bypass it, we must learn the basics of how it works.
Censorship Methods in China
China blocks many IP Address that webservers use (such as Google IP ranges, Facebook, etc). If the website is on a shared hosting server, many other websites end up being blocked as well.
In order to access a website, your Internet connection / computer needs to know the website’s IP Address. This is found by using a DNS server. Your ISPs default DNS server can end up returning incorrect information and log the request if you try to go on a website that China doesn’t want you to go on.
Everytime someone visits a website, the data of a website gets sent back to the user from the website’s server. China monitors these connections. China also denies connections that have suspicious keywords, like “Tiananmen” (location of protests in China) in the URL of the website.
Keyword Blocking is also used in TCP packets. If the packet returned from the website contains certain keywords, the connection will be dropped.
China Unicom is able to detect VPN connections, even if the connection is encrypted. Sadly, those connections are blocked. I’m not sure if other ISPs in China do that, but it is likely.
How to Circumvent These Methods
Now for the fun part. We’re going to circumvent these methods. It may be difficult, or not even work, but these methods are definitely worth a try.
Use a VPN
Although China Unicom, and possibly other ISPs block VPN connections, you should still attempt to connect to a VPN if you’re not using China Unicom.
Use an Alternative DNS Server
In order to bypass DNS blocks, you can use an alternative DNS server. We recommend OpenNIC.
It actually is likely that Tor is not blocked with your ISP. The people from Tor work very hard on circumventing censorship for people in countries like China and Iran.
If you want to use Tor in China, you must connect with a bridge (https://bridges.torproject.org/).
A Few Mirrors for Tor if the Main Website is Blocked:
Proxies are another great way to circumvention censorship. Sadly, most are blocked, and it is difficult to find proxies that aren’t blocked.
Proxies.By is a great resource for open proxy servers.
Hopefully this post has been helpful for you. If none of these methods work, I found a PDF that evaluates circumvention tools and more details on the Great Firewall of China:
Creative Commons Image found at WikiMedia Commons.