Vertical handoff is one of the most important issues in the heterogeneous networks. While Lee et al. introduced a selective advance reservations and resource-aware handoff direction (SARAH) mechanism in order to provide a fast and efficient handoff with combination of layer 2 (L2) and layer 3 (L3) communications, there was a drawback that there was no consideration of handoff between heterogeneous network. In this paper, we improve the mechanism by providing security functions such as the neighbor-mapping server that binds IP address and MAC address with security support. At first, we discuss security issues in SARAH and proposed enhanced protocol. Finally, we show simple implementation results of our design in order to verify the practical aspects of our design.