A forced routing information modification model for preventing black hole attacks in wireless Ad Hoc network The black hole attack in wireless Ad Hoc network is major issue that needs efficient solutions. In black hole attack more than one node can be malicious. Most of the time black hole attack occurs in large Ad Hoc networks. The black hole attacks in wireless Ad Hoc network creates misunderstanding in network by introducing error in routing information that leads the node to select wrong path hence data lose occur. We have proposed a novel architecture of FRIMM (A Forced Routing Information Modification Model) prevents black hole attacks in wireless Ad Hoc network by introducing automatic error correction in routing information that leads the node to select correct path thus secure transmission will take place between source and destination. In this model we assume that the network is centralized. In this model we have used the popular protocol AODV (Ad Hoc On-Demand Distance Vector). It is constructed on three basic devices such as server, access points and nodes. Server and access points are fixed and has permanent infrastructure with each other. But the connections of nodes with access points are on Ad Hoc bases. The node can be any device a laptop, mobile phone etc. We used two technologies for communication between sever and access points and the access points to nodes. We have used WiMax technology (IEEE standard 802.16 10 to 66 GHz range) for the communication between server and access point, other technology WiFi (IEEE standard of 802.11b/g 2.400 GHz to 2.487 GHz) for the communication between access point and node. No nodes can communicate with sever without having connection with an access point, because the server does not have the capability of WiFi technology. We have deployed three access points in this scenario. Suppose a node come and generates request to access point for connection. The node gets response from any of the access point near to it depending upon the strength of signal. Suppose access point 1 response its request. The access point will do- two amendments in its routing table first adding its MAC address in its routing table then assigning ID (N) to node. Secondly sends the updated routing table to other access points and to the server. Now another node comes into the network broadcast request for accessing access point. Two responses reached to the node, first from access point 2 and other from a malicious node saying that I am the server. In this situation the node decides to communicate directly to the server. Here black hole attack occurs, because server has no capability to communicate directly to node. The access point waits for few minutes then scan the network weather the node has leave the network or become the victim of black hole attack. After scanning the network the access point detect that node is communicating with undetermined node (M), so that access point 2 will listen the traffic between victim node and the malicious node then fetch MAC address of that malicious node. The access point also collects the information about the requests sent by the node towards malicious node. In the mean time access point 2 alerts all other access points within the network and also update the server about the black hole attack and sends MAC address of that malicious node and also send the collected requests of node to malicious node. After having the MAC address of malicious node the server will attack the black hole by the help of access point by introducing jamming style DoS attack now server can force the node by the help of access point to divert its traffic towards access point. Node agreed to divert its traffic towards access point then the communication will be started between node and server through access point. This force leads the node to modify its routing table, so node will divert its traffic towards access point and the communication will be started between node and server through access point.