Networks Associates, Inc.

Gregor A Glawitsch

A system and a method for preventing a spoofed denial of service attack in a networked computing environment is described. A hierarchical protocol stack is defined. The hierarchical protocol stack includes a plurality of communicatively interfaced protocol layers with at least one session-oriented protocol layer. A packet requesting a session with the session-oriented protocol layer is received from the networked computing environment. The request packet includes headers containing a source address of uncertain trustworthiness. The request packet is acknowledged by performing the following operations. First, a checksum is calculated from information included in the request packet headers. A request acknowledgement packet is generated. The request acknowledgement packet includes headers containing the checksum as a pseudo sequence number and the source address in the request packet headers as a destination address. Finally, the request acknowledgement packet is sent into the networked computing environment. An acknowledgement packet is received from the networked computing environment. The acknowledgement packet includes headers containing an acknowledgement number. The acknowledgement packet is validated by performing the following operations. First, a validation checksum is calculated from information included in the acknowledgement packet headers. Then, the validation checksum is compared to the acknowledgement number of the acknowledgement packet. No state is maintained by the authenticating system until the comparison has succeeded.

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Milpitas, CA, United States of America

Gregor A Glawitsch