Security is an important need in wireless mesh networks to give safe and shared information between wireless non-static nodes. In wireless network nodes has ability to act correctly and route the packets. Wireless mesh networks unusual method of producing, keeping and sharing information ability of mobile objects to show spontaneous and cheap adjusting arrangement itself a mobile ad hoc network (MANET) is a continuously self-configuring, infrastructure-less network of mobile devices connected wirelessly. In this paper I have described different defense intrigue according to my knowledge, and also as per different research papers studied. As per my knowledge, I have described drawbacks of Gray Hole Attack, or Selective Forwarding Attack, thus providing better way to understand the Gray Hole Attack in better way and the proposed solution. In the proposed solutions, I have tried to give better solutions in the sense of detection and prevention of Gray Hole Attack or Selective Forwarding attack.
MANET, Black Hole and Gray Hole attacks, MD5, AODV.