Mobile ad-hoc networks (MANETs) are well known to be susceptible to various attacks, due to features such as lack of centralized control, dynamic topology, limited physical security and energy constrained operations. In this paper, we focus on preventing Sybil attack and Intruder nodes (malicious node). We are presenting a novel and secure authentication of nodes as soon as they comes in to the network (checks the identity of a new node) and then checking the RSS value of node continuously and accurately detecting the sybil identity in the network.