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In order to do this, you need ssh access to a server that has the characteristics you are looking for. So, for example, to emulate the Chinese user experience, you need a server in China that you can ssh to.
Starting the proxy
Execute this command in a local shell:
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ssh should prompt you for a password and then hang. Ctrl-C will kill the proxy.
Using the proxy
Now go to your browser and set it to point at your proxy. These screenshots were taken from Firefox 39.
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Bear in mind that websites you might commonly use to test your connection (like Google) are blocked in other countries, often the same ones whose network conditions we wish to simulate. Try other sites, like tudou or yandex.
Denouement
When you're done with your proxy, kill the ssh command and set your connection settings back to "No proxy".