Now a day, it is no longer optional to have security solutions even inevitable for every kind of organizations and individuals. There are number of generic tools which are common for organizations as well as for individual users to provide security which includes; Anti-Spam, Anti-Virus etc., and network security have become essential issue in MANET. Security is one of the main issues in the MANET especially with respect to size and complexity of the network. The aim of the thesis is to discuss different aspects of security in MANET (e.g. multi-layer intrusion detection technique in multi hop network of MANET, security problems relates between multihop network and mobile nodes in MANET etc) and also implement some of the solutions (e.g. comparative study of different routing protocol (AODV, DSR and TORA) security threats within MANET network like intruder behavior, tapping and integrity, MANET link layer and network layer operations with respect to information security etc) with respect to MANET network. This report also discusses different number of scenarios of MANET network which we implement in our simulation. In our simulation we use to implement different routing protocols and also did comparative study that which one is better with respect to different aspects. We also use to implements mechanisms of intruder behavior, tapping and integrity, and MANET link layer and network layer operations with respect to information security.