An active Detecting Method Against SYN Flooding

SYN flooding attacks are a common type of Distributed Denial-of-Service (DDoS) attack. Early detection is desir-able but traditional passive detection methods are inaccu-rate in the early stages due to their reliance on passively sniffing an attacking signature. The method presented in this paper captures attacking signatures using an active probing scheme that ensures the efficient early detection. The active probing scheme–DARB obtains the delay of routers by sending packets containing special Time-to-Live set at the IP headers. The results of the probe are used to perform SYN flooding detection, which is reliable and with little overhead. This approach is more independent than other methods that require cooperation from network de-vices. Experiments show that this delay-probing approach distinguishes half-open connections caused by SYN flood-ing attacks from those arising from other causes accurately and at an early stage.