METHOD, DEVICE AND SYSTEM FOR PREVENTING DOS ATTACK AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To realize a general measure against a DoS attack, including address- unsettled-type DoS attack and to realize the general measure against the address unsettled-type DoS attack, as the added value of ISP. SOLUTION: The different-type of safety identifier is added to a communication packet in accordance with the degree of safety recognition performed on the communication packet. Priority control corresponding to the safety identifier is performed on the transfer route of the communication packet is performed. The safety identifier is added to the packet which will not perform safety recognition.