IARJSET ISSN (Online) 2393-8021 ISSN (Print) 2394-1588 International Advanced Research Journal in Science, Engineering and Technology Vol. 5, Issue 11, November 2018 Copyright to IARJSET DOI 10.17148/IARJSET.2018.5114 20 A Survey on Prevention & Elimination of MANET Attacks Praveen Kumar Joshi 1 , Anindita Saha 2 Department of CSE, BTKIT Dwarahat 1,2 Abstract: MANET (Mobile Ad-hoc Network) which is well known as infrastructure less network finds its application in situations where setting up of network should be impromptu. But this advantageous aspect of MANET can be used as a weakness to intrude into the system. That’s why it becomes very important to tackle this scenario. In this paper two of the major attacks i.e. Black hole attack and Gray hole attack are discussed. First is active kind of attack in which malicious node participates actively whereas later one is passive attack, which is difficult to detect because malicious nodes do not drop the packets every time. So, it is quite evident that first one is eliminated and later one is prevented. This paper attempts to put forward all such aspects of MANET. Keywords: Black hole attack, Gray hole attack, MANET I. INTRODUCTION Mobile Ad-hoc Network (MANET) is an on-demand network that self-configures using wireless connection. The topology of a MANET changes quickly and unpredictably. As the devices in this network are organizing all by themselves and without the interference of any user, they sets-up really fast. This is the reason why it is perfect to be used for urgent situations like rescue operations and emergency medical situations. The devices involved in MANET are part of it. This means that there is no such requirement of any pre-existing infrastructure. On the basis of these grounds it is well-known as infrastructure-less network. The advantage of dynamically changing topology is the biggest loophole of MANET as it makes it prone to several issues such as QoS (Quality of Service), scalability, security, memory overhead etc. The self-configuring property of Mobile Ad-hoc network makes it usable in variety of domains such as law enforcement; emergency search-and-rescue operations, different industries also use it for supervision purpose. II. VARIOUS KINDS OF ATTACKS IN AD-HOC NETWORK Although Ad-hoc networks are used in variety of applications but because of its ever changing topology they are susceptible to various attacks like traffic relaying and traffic generation. This paper discusses wo well known attacks- black hole and gray hole attack and how these traffic relaying attacks can be avoided. . The Black hole and Gray hole attacks are security attacks which falls under the network layer attacks, they exploit reactive routing protocols of MANET such as DSR, AODV etc., to drop the packets in the network [1]. A. Balck Hole Attack: It is a DoS(Denial of Service) attack. In this, an intruding node replies to the request of the source node for the best possible path. The intruding node gives an implication that shortest possible path is through it. But, as soon as it gets the packet which is to be delivered to the destination, it drops the packet straight away. This way the malicious node affects the network actively and causes the loss of information. Fig. 1: Node1 is malicious