Abstract
Fuzzy rule-based technique, combining fuzzy logic and expert system methodology, not only is capable to deal with uncertainty in intrusion detection but also allows the most flexible reasoning about the widest variety of information possible. It can be used in both anomaly and misuse detections. This paper presents a method for detecting intrusion based on fuzzy rule-based technique. Fuzzy Reasoning Petri Nets (FRPN) model is used to represent fuzzy rule base and to derive the final detection decision as an inference engine. FRPN have parallel reasoning ability and are readily used into real time detection. An illustration example of TCP SYN flooding attack detection is provided.