With recent advances in wireless communication technology, mobile computing is an importance research area. Mobile IP is designed to provide IP services to roaming nodes. Mobile users take advantage of this protocol to obtain the services as if they were connected to their home network. In many cases mobile users is connected through a wireless link and is protected by corporation's firewall in virtual private network. In order to have a successful deployment of Mobile IP as an extension of a private network, security services should be provided as if the mobile node were attached to its home network. In this paper, we propose the security mechanism of combining Mobile IP and IPSec tunnels, which can provide secure traversal of firewall in a home network. The simulation results show that the proposed mechanism provides the secure and efficient communication.