Even conventional VPN is not enough. The Great Firewall of China (
https://en.wikipedia.org/wiki/Great_Firewall) is a mix of DNS poisoning, deep packet inspection, and traffic and usage analysis based on real time ML. It is very smart and adaptive, and will block most mainstream VPN services, including IPSEC, standard OpenVPN, SSH tunnels, (of course) SOCKS and http proxies.
Besides blocking entire sections of the net outright (like Google address blocks), poisoning controversial domains, etc, even if it can't directly inspect the traffic due to good encryption (say in the instance of OpenVPN or IPSEC), it will slowly degrade and eventually null-route your traffic over the course of minutes, depending on its judgement of the likelihood (based on packet structure and history) that your activity isn't "normal" usage.
Currently the only functional ways of getting around the GFW is VPN through stunnel (TCP OpenVPN traffic re-wrapped in TLS, thus pretending to be https traffic, and incurring triple TCP performance penalties), similar convoluted protocols like Shadowsocks, obfsproxy, and other China specific tools.
Besides blocking entire sections of the net outright (like Google address blocks), poisoning controversial domains, etc, even if it can't directly inspect the traffic due to good encryption (say in the instance of OpenVPN or IPSEC), it will slowly degrade and eventually null-route your traffic over the course of minutes, depending on its judgement of the likelihood (based on packet structure and history) that your activity isn't "normal" usage.
Currently the only functional ways of getting around the GFW is VPN through stunnel (TCP OpenVPN traffic re-wrapped in TLS, thus pretending to be https traffic, and incurring triple TCP performance penalties), similar convoluted protocols like Shadowsocks, obfsproxy, and other China specific tools.