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1. (WO2002003084) METHOD FOR PREVENTING DENIAL OF SERVICE ATTACKS

Pub. No.:    WO/2002/003084    International Application No.:    PCT/US2001/019492
Publication Date: Jan 10, 2002 International Filing Date: Jun 18, 2001
IPC: H04L 29/06
Applicants: NETRAKE CORPORATION
Inventors: MAHER, Robert, Daniel, III
BENNETT, Victor, A.
Title: METHOD FOR PREVENTING DENIAL OF SERVICE ATTACKS
Abstract:
A method and apparatus for preventing denial of service type attacks on data networks is described. The method (500) involves scanning the contents of the data packets flowing over the data network using a traffic flow scanning engine (502). The data packets are reordered and reassembled (504) and then the payload contents are scanned (510) to determine whether they conform to predetermined requirements (512). Data packets which do not reorder or reassemble correctly (506) or which do not conform to the predetermined requirements (512) may be dropped (508). The traffic flow scanning engine is further operable to determine whether the data packets are associated with validated traffic flows (514). Those data packets associated with validated traffic flows are assigned to a higher priority (520) while those not associated with a validated traffic flow are assigned to a low priority (516), which may occupy no more that a predetermined maximum of the available bandwidth (518).