23. The system of claim 16 , wherein the pre-matching module comprises a string matching module configured to implement a string-level matching to determine whether a string specified by the one or more conditions is present in any packet of the packet stream.
23. The system of claim 16 , wherein the pre-matching module comprises a string matching module configured to implement a string-level matching to determine whether a string specified by the one or more conditions is present in any packet of the packet stream. 24. The system of claim 23 , wherein the pre-matching module comprises a passive overflow pattern matching module configured to implement passive matching based on overflow patterns that occur between packet characters or strings within a defined range.