The mobile adhoc networks have become a major component of the future network development due to their ease of deployment, self configurability, flexibility and independence on any existing network infrastructure Mobile ad-hoc network have the attributes such as wireless connection, continuously changing topology, distributed operation and ease of deployment. We present a design space analysis of the problem of providing Internet connectivity for mobile ad hoc networks (MANETs). Currently there are a plethora of proposals to solve this problem in the research community. However, we argue that many of the existing designs suffer from complexity and design solutions that have not been properly evaluated. One reason for this is the lack of implementations. For widening the coverage area of the MANET there is a growing need to integrate these ad hoc networks to the Internet. For this purpose we need gateways which act as bridges between these two different protocol architectures. The gateway discovery in hybrid network is considered as a critical and challenging task. In this paper the AODV reactive routing protocol is extended to support the communication between the MANET and the Internet. We have carried out a systematic simulation based performance evaluation of the different gateway discovery approaches using NS2 under different network scenarios. The performance differentials are analyzed on the basis of three metrics - packet delivery fraction, average end-to-end delay and normalized routing load.