Simulation of Gray Hole Attacks in MANETs Using NS2

The current era is defined by pervasive mobility, which significantly influences networking technologies. Evaluating new communication systems, particularly in terms of their reliability and adaptability within the Internet, has become a key focus for modern research. Thus, this area is focused on researchers to provide solutions for pressing challenges in Mobile Ad-Hoc Networks (MANETs). In this context, Mobile Ad Hoc Networks (MANETs) have emerged as a prominent area of study due to their decentralized structure and dynamic topology, making them suitable for environments lacking fixed infrastructure. However, these very characteristics also render MANETs highly vulnerable to security threats such as gray hole attacks. This paper investigates the impact of gray hole attacks on the Ad hoc On-Demand Distance Vector Routing (AODV) and Dynamic Source Routing (DSR) protocols. The results of these protocols were analyzed using the NS2.35 simulator on Ubuntu 22.04. A malicious node is introduced in the simulation, which initially behaves normally during route discovery but later drops data packetsselectively. The study evaluates the effects of malicious node behavior on critical performance metrics such as packet delivery ratio, end-to-end delay and throughput. The findings underscore the susceptibility of DSR to such attacks and explore potential countermeasures to improve the security and robustness of routing in MANETs.