Abstract: MANET’s is the form of wireless network (WLAN). And Ad-hoc network is infrastructure less. They does not need any centralized system or any kind of infrastructure. Each node in the Ad-hoc network will act as router and will route the packet to the destination. DSR is an on-demand routing protocol. This means routes are not pre-established routes and routes are only active during the transmission. The main problem in the MANET is attack on data. As we know in MANET we cannot differentiate which node is the attacker node and which is benign node. So, the attacker node can easily capture the data. And these types of attacks are known as Black-hole, worm-hole and gray-hole attack. So, identifying which node is genuine node or for preventing the data from the attacker node is necessary in MANETs. This paper provides the good technique which helps in preventing from these types of routing attacks during data transmission. And this leads to the secure communication as we select the intermediate node on the basis of its energy and buffer state. This paper consider the two parameters for selecting the forwarding nodes, first one is their energy state and their buffer value. Only those nodes will participate in the transmission which have their energy state equal to some threshold value and have the less buffer value. Because the attacker nodes have less energy due to continuously sending the RREP message to the nodes and have high buffer value as it always attract the neighbor nodes for transmission. So, the implemented technique only selects the nodes which seem to be genuine on the basis of measuring two factors its thresh-hold energy and buffer value of the IN. And this result into the less packet loss as compared to the DSR. And even if the attacker captures the packets, the packets will be in encrypted form. Attackers have to decrypt the packet for reading it and its really hard to decrypt them. The packet loss will be less in the proposed technique and throughput will be increased

Keywords: DSR, WLAN, MANET, IN, RREP and RREQ.