The great firewall of China may be just an illusion in technical terms. This article describes the details of how things work…. Basically when “banned content” is detected, both ends of the connection are sent a flood of tcp reset packets. Which (if both sides are designed to pay attention to) means that the two computers “hang up” assuming the other side reset the connection. But, while most current PC operating systems obey the reset packets…. it’s not something that is imperative. (You might think of this as a targeted/surgical denial of service attack using TCP reset packets…) The article goes a bit deeper though….