IJSRST1841283 | Received : 12 Feb 2018 | Accepted : 26 Feb 2018 | January-February-2018 [ (4) 2: 1464-1471] © 2018 IJSRST | Volume 4 | Issue 2 | Print ISSN: 2395-6011 | Online ISSN: 2395-602X Themed Section: Science and Technology 1464 AODV Routing Protocol to Defence Against Packet Dropping Gray Hole Attack In MANET M. Jeevamaheswari*, R. Anandha Jothi, V. Palanisamy Department of Computer Applications, Alagappa University, Karaikudi, Tamil Nadu, India ABSTRACT A Mobile Ad Hoc Network (MANET) is self-organizing multi-hop network. In general MANET is characterized by the open wireless medium and open to anyone. Due to the unique characteristics such as dynamic network topology, limited bandwidth, limited battery power and infrastructure less network environment, MANET is lacking in centralized authorization and highly vulnerable to malicious gray-hole attacks. Thus the security is a critical problem when implementing MANET. Every node in MANET is vulnerable and the good performance of the network is depends on nodes or participate path from the source to a given destination. It is very tedious to sense some attacker nodes when it becomes a part of network. Ad-hoc on-demand distance vector (AODV) protocol is a popular reactive routing protocol but exposed to well-known packet dropping attack, where a malicious node purposely drops some packets without forwarding them to destination. In this paper, we discuss the security mechanisms, namely Data routing information (DRI), and cross-checking operations to defend against packet dropping attack in MANET. Keywords : AODV, DRI, Packet Dropping, Routing I. INTRODUCTION A Mobile Ad Hoc Network (MANET) is a collection of well-defined mobile nodes. In this network is an infrastructure less network because such network does not have any fixed infrastructure. The mobile nodes are dynamically change the topology and paths between themselves to transfer the data packets from one node to another node and it is self-organizing network, Each and every mobile nodes are acts as a host and router .when Request (REQ)/Replay (REP) information from/to in the network and route determining and preserving routes other nodes in network. MANET is a wireless nature to make some susceptible to the security attacks. The network layer is severely affected by the security attack especially on gray-hole attack which comes belong to the security attack. such kind of network has various applications like Military , Battle fields, disaster recovery ,earthquakes, and setup virtual class & conference rooms for educational applications multi –user games, robotics pets for entertainment applications, remote weathers for sensors, earth activities for sensor network emergency relief scenario etc. Naturally the MANET has dynamically changed their behavior, in this nature easily vulnerable for extensive kind of attack. The Individualities of MANET pose together challenges and opportunities in attaining security goals. We proposed a technique to define multiple gray-hole nodes cooperative as group. In this studied work was tiny modify the AODV routing protocol and its Data Routing Information (DRI) Table in addition to the stored and present routing table. The rest of this paper is planned as follows. In Section 2, studied some related work, Section 3, explained gray hole attack and its functionalities. Section 3, implementation of MAODV and AB-DRI table with