Date Added: Dec 2011
It is a known fact that computer and network systems have certain design flaws which leads to security hazards. Intruders can exploit the security flaws and break the computer systems, and is very expensive and sometimes nearly impossible to fix all the design and programming errors. This suggests that prevention-based approaches are no more reliable and hence intrusion detection is needed as a last line of defense. This paper presents a nomenclature of intrusion detection systems that is used to do a survey and identify a number of research prototypes. This classification consists of detection principles and the operational aspects of intrusion detection system. These classifications can be used efficiently leading towards a number of future research works in the field of intrusion detection.