A novel method for stateful packet classification that uses hardware resources for performing stateless lookups and software resources for performing stateful connection flow handshaking is provided. To classify an incoming packet from a network, some embodiments perform stateless look up operations for the incoming packet in hardware and forward the result of the stateless look up to the software. The software in turn uses the result of the stateless look up to perform the stateful connection flow handshaking and to determine the result of the stateful packet classification.