Detection as well as removal of black hole and gray hole attack in MANET

A lot of mobile network works in today network Mobile Ad-hoc Network is a special kind of network which works on variable (not fixed) networks. Due to dynamic characteristics and addictive functionality, these are suffers from various types of attacks. Black-hole and gray-hole attack is one type of attack which harms and attacks on MANET. In this attack the malicious (unwanted node) distract the data packets that it feels is having shortest and the freshest route to the destination node so sender forwards all the data packets to it. After receiving the data packets, it drops them to create a Denial of service attack or processes to extract information from the packet. In this paper a technique is being proposed for detection of the black-hole or malicious node. In this technique, a new procedure a kind of trap method is added in AODV protocol for the detection of malicious nodes. When the Black-hole node is detected after that an alarming method is triggered to make other nodes aware of malicious nodes.