  Security is one of the major issue in wired and wireless network but due to
the presence of centralized administration not difficult to find out
misbehavior in network other than in Mobile Ad hoc Network due to the absence
of centralized management and frequently changes in topology security is one of
a major issue in MANET. Only prevention methods for attack are not enough. In
this paper a new Intrusion Detection System (IDS) algorithm has proposed
against selfish node attack to secure MANET. Here the behavior of selfish node
is unnecessary flooding the information in network and block all types of
packets transferring between the reliable nodes. Proposed IDS Algorithm
identifies the behavior of selfish node and also blocked their misbehavior
activities. In case of selfish node attack network performance is almost
negligible but after applying IDS on attack network performance is enhanced up
to 92% and provides 0% Infection rate from attack.
