Several protocols of address autoconfiguration in the mobile ad hoc network (MANET) are present in the current literature. Although some of these protocols perform decently in sparse and small networks, but exhibit poor performance (e.g., single point of failure, storage limitation, large protocol overhead and so on) when the network is either dense or very large. In this paper, we propose an efficient and scalable address autoconfiguration protocol that automatically configures a network by assigning unique IP address to every node with low overhead and minimal cost. Evenly distributed Duplicate-IP Detection Servers are used to ensure the uniqueness of an IP address during IP address assignment session. In contrast to some other solutions, the proposed protocol does not exhibit any problems pertaining to leader election or centralized server-based solutions. Furthermore, grid based hierarchy is also used for efficient geographic forwarding as well as for selecting Duplicate-IP Detection Servers. Through simulation results we demonstrate scalability, robustness, low latency, fault tolerance and some other important aspects of our protocol.