Network attack protection system and method and flow control device

The invention provides a network attack protection system and method and a flow control device, and the system comprises a router which is used for obtaining the backup flow of network flow and transmitting the backup flow to a detection device; after a second flow traction instruction is received, dragging the network flow to the cleaning device; and discarding the network flow after a flow discarding instruction is received; a detection device which is used for analyzing the received backup flow and obtaining feature information of the backup flow; a flow control device which is used for judging whether the network flow meets a preset discarding condition or not according to the feature information of the backup flow, and sending a second flow traction instruction to the router when thejudgment result is that the network flow does not meet the preset discarding condition; when the judgment result is that the network flow meets the preset discarding condition, sending a flow discarding instruction to the rou