That's because the GFW allowed it, GFW has no problems to block any VPN at will.
GFW is sophisticated beyond imagination, one way to detect VPN traffic(or SSL, or SSH) is to observe its patterns and where the traffic is going. It's not too hard to have a blacklist of all VPN vendors too.
shadowsocks was designed to bypass it(to make traffic looking random), I recall its developers were visited by cops and warned to stop doing that.
It's said China built the largest LAN on earth, the government is just too scared by its people to get educated, it's a true parallel universe.
GFW is sophisticated beyond imagination, one way to detect VPN traffic(or SSL, or SSH) is to observe its patterns and where the traffic is going. It's not too hard to have a blacklist of all VPN vendors too.
shadowsocks was designed to bypass it(to make traffic looking random), I recall its developers were visited by cops and warned to stop doing that.
It's said China built the largest LAN on earth, the government is just too scared by its people to get educated, it's a true parallel universe.