Security is an essential requirement in mobile ad hoc networks to provide
protected communication between mobile nodes. Due to unique characteristics of
MANETS, it creates a number of consequential challenges to its security design.
To overcome the challenges, there is a need to build a multifence security
solution that achieves both broad protection and desirable network performance.
MANETs are vulnerable to various attacks, blackhole, is one of the possible
attacks. Black hole is a type of routing attack where a malicious node
advertise itself as having the shortest path to all nodes in the environment by
sending fake route reply. By doing this, the malicious node can deprive the
traffic from the source node. It can be used as a denial-of-service attack
where it can drop the packets later. In this paper, we proposed a DPRAODV
(Detection, Prevention and Reactive AODV) to prevent security threats of
blackhole by notifying other nodes in the network of the incident. The
simulation results in ns2 (ver- 2.33) demonstrate that our protocol not only
prevents blackhole attack but consequently improves the overall performance of
(normal) AODV in presence of black hole attack.