It would be easy to block on protocol level. Countries that block VPNs usually progress to that level pretty fast once they discover that simple IP blocks don't work.

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jszymborski 9 days ago | parent [-]

The traffic looks like any other web page.

	▲	int_19h 9 days ago \| parent [-]
		I doubt that is the case once you do statistical analysis of it. Advanced VPN tunneling protocols, for example, have to take a lot of special measures to conceal their nature from China's and Russia's deep packet inspecting firewalls.