Patent ID: 8374185

Claim:
A packet inspection device comprising a computer readable medium containing program codes to control the packet inspection device for: storing, comparing, and screening to select a packet in presence of 3-way handshaking underway at the Transmission Control Protocol (TCP) layer, for converting information into a hashing function value, and for storing the hashing function value, so as to allow header information of the packet to be converted into the hashing function value and the hashing function value to be compared and stored to create a session connection upon determining that information stored does not match the hashing function value resulting from the conversion, and perform packet state comparison and packet screening upon determining that information stored matches the hashing function value resulting from the conversion; and creating a transmission connection according to the screened packet, wherein the program codes further control the packet inspection device for: converting the header information of the packet into an address value; converting the header information of the packet into key values; and retrieving information in the address value, comparing the information in the address value with the key values of the packet in sequence, incorporating a corresponding one of the key values into the address value upon determination of absence of a match, and performing the packet state comparison and packet screening upon determination of presence of a match, wherein a plurality of hashing functions are provided for converting the same header information of the packet into the key values, and the address value has a plurality of information that are comparable with the key values of the packet that are converted from the header information of the packet by the hashing functions, wherein each of the plurality of information relates to a packet record for comparison of the key values of the packet, so as to decrease a chance of creating a connection in vain when mapping different packets to the same address value, and the key values are created by the plurality of hashing functions based on one header information of the packet.