The motivation of this paper is the need for security on Mobile IP (MIP) enabled networks. Nowadays, 802.11 networks rely on the 802.1X authentication protocol for authenticating mobile nodes requiring network access. MIP protocol could be used to enable those mobile nodes to access a network as their home network, without any IP configurations. However, many security issues confer some vulnerabilities for MIP enabled devices (mobility agent and users). Our approach enables MIP agents to get keys for message authentication purposes while (de)registering a mobile node in a network and provide trustworthy information about MIP agents that serve future roaming networks to mobile nodes. Furthermore, fast and secure MIP handovers are gracefully handled with a slight change in the MIP protocol. Finally, with our approach we achieve a functional, integrated security architecture handling both link layer and network layer mobility.