IPv4 will be out of use soon, so we have IPv6 now, and which are used by Facebook, Google, Twitter and some other famous websites blocked in China.
If your broadband supports IPv6 access, then you can visit those IPv6 sites directly, if not, you can do that indirectly with some third-party tools, such as gogoCLIENT.
The following will show you how to access blocked sites via gogoCLIENT:
1. Register a gogo6 account
On the gogoCLIENT page, click on the "Sign Up" button, enter your email address or connect with Facebook, Google, Twitter or some other social network and create a gogo6 account.
2. Download gogoCLIENT
After registration, log in and open the gogoCLIENT page mentioned above again, then you can down the gogoCLIENT clients.
Up till now, gogoCLIENT supports 32 bit and 64 bit Windows systems with both Basic Version and Home Access Version (= basic version + home access).
Besides, gogoCLIENT also supports Linux/Unix/MacOS/BSD systems with source code, which need to be installed via the MAKE command, and you can check out the Guide (PDF) file for more details. The following will show you how to use the basic version on Windows.
3. Connect gogoCLIENT
After installation, run the gogoCLIENT Utility client, and click on the "Connect" button, if the connection is successful, then you can get access to the blocked sites with IPv6 addresses via any of the following 3 ways:
3.1 Via suffix
In the end of the domain of any IPv6 supported site, add the following suffix:
Take Twitter for example, you can visit its website via the following URL:
3.2 Via PAC
Ago, you could open the network connection settings page, select the "Automatic proxy configuration URL" option, and enter the following URL:
Then you were able to access the blocked sites with IPv6 supported.
But now, the above PAC (Proxy auto-config) file is not workable any more, and I haven't found any alternatives yet.
3.3 Via Hosts
As mentioned before, you can unblock those blocked sites by adding their IPv4 addresses into the hosts file, now with gogoCLIENT, you can also add their IPv6 addresses.
On Windows, you can find the hosts file in the following address:
On Max OS X, you can find and open the hosts file by entering the following command line on the Terminal application:
sudo vi /private/etc/hosts
After that, visit this ipv6-hosts (Chinese) page, copy the IPv6 addresses as well as their domains of Google, YouTube, Twitter and/or some other sites listed, and paste them into the hosts file, then you can unblocked those sites.
For those blocked sites which are not listed, you can find if they have any IPv6 addresses via the IPv6 Test web app.