  Mobile ad hoc networks (MANETs) are a set of mobile nodes which are
self-configuring and connected by wireless links automatically as per the
defined routing protocol. The absence of a central management agency or a fixed
infrastructure is a key feature of MANETs. These nodes communicate with each
other by interchange of packets, which for those nodes not in wireless range
goes hop by hop. Due to lack of a defined central authority, securitizing the
routing process becomes a challenging task thereby leaving MANETs vulnerable to
attacks, which results in deterioration in the performance characteristics as
well as raises a serious question mark about the reliability of such networks.
In this paper we have attempted to present an overview of the routing
protocols, the known routing attacks and the proposed countermeasures to these
attacks in various works.
