Mobile IP and Network Mobility are the IETF proposals to obtain mobility. However, both of them have routing limitations, due to the presence of an entity (Home Agent) in the communication path. Those problems have been tried to be solved in different ways. A family of solutions tries to improve the routing by locating closer Home Agents making shorter the communication path. These techniques require a method to discover a close Home Agent from the Mobile Device. We proposed peer-to-peer based solution, Peer-to-Peer Home Agent Network, in order to discover a close Home Agent. This paper defines the necessary mechanisms to make this solution secure based on a mechanism named Secure Join Procedure.