Abstract new address must be edited into various configuration ” files. This paper describes a new protocol for transparently rout-ing packets to mobile hosts operating in a large internet-work. The protocol, called the Mobile Host Routing Proto-col (MHRP), allows any host to become mobile at any time, yet there is no penalty for a host being “mobile capable,” since the protocol automatically uses only the standard in-ternetwork routing mechanisms and adds no overhead when a mobile host is currently connected to its home network. The paper concentrates on the design of MHRP as it ap-plies to the Internet using IP. Mobile hosts use only their “home ’ ’ IP addresses, regardless of their current location in the Internet. No changes are required in stationary hosts that communicate with mobile hosts, and no changes are required in mobile hosts above the IP level. MHRP intro-duces several new features to provide better robustness for routing to mobile hosts, and provides better scalability to very large numbers of mobile hosts than previous mobile host protocols. 1.