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.
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.
The traffic looks like any other web page.
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.