This paper presents the design, implementation, and performance evaluation of an approach to supporting host mobility in the wireless Internet. We observe that a single IP address conventionally serves dual purposes: a network-level routing directive and an endpoint identity of a certain session in transport or upper layers. Therefore, when a host affiliates with a new IP address due to movements, any pre-established active session thereupon suffers outage. Unlike prior schemes exploiting mobility agents, we propose to let a host use two IP addresses for network- and transport-layer identifications, respectively, and introduce a translation table that associates the two identities. Such an association results from querying or dynamic updates to the Domain Name System, or from direct message exchanges between two communication peers so as to optimize delivery paths. Simulation results show that our scheme outperforms counterpart Mobile IP and Mobile IPv6, in terms of communication delay, packet error rate, message space overhead, and potential packet loss during handoffs. Additionally, qualitative discussions conclude that our proposal lends itself to IPv4 and IPv6 interconnected networks, or multi-tier environment such as wireless Local Area Networks and mobile telecommunication overlay systems.