Mobile Ad Hoc Network (MANET) has emerged as a new technology to provide
anytime, anywhere communication. Increasingly wireless ad-hoc networks are being
employed in the tactical battlefield, emergency rescue and search missions, as well as
civilian ad-hoc situations like classrooms and conferences.Due to its unique
characteristics, mobile ad hoc networks (MANETs) are more vulnerable to malicious
attack and the absolute security in the mobile ad hoc network is very hard to achieve.
Prevention methods as cryptographic techniques alone are not sufficient to make them
secure; therefore, efficient intrusion detection must be deployed and elaborated to
facilitate the identification of attacks. An Intrusion Detection System (IDS) aims to
detect malicious and selfish nodes in a network. The intrusion detection techniques
used for wired networks may no longer be effective and sufficient when adapted
directly to a wireless ad-hoc network, thus existing methods of intrusion detection
have to be modified and new methods have to be defined in order to work effectively
and efficiency in this new network architecture. In this paper we give a survey of
different architectures and methods of intrusion detection systems (IDSs) for
MANETs accordingly to the recent literature.