SECURE COMMUNICATION WITH MOBILE HOSTS

A method for secure data communication with a mobile machine in which a data packet is received from the mobile machine having a particular network address. A pool of secure addresses is established and a data structure is created to hold address translation associations. Each association is between a particular network address and a particular one of the secure addresses. If the received data packet is a secure data packet an association between the received data packet's network address and a secure address in the data structure is identified and the data packet's network address is translated to the associated secure address before forwarding the data packet on to higher network protocol layers. When the received data packet is not secure it is passed it on without address translation to the higher network protocol layers. For outgoing packets addressed to a secure address, the secure address is translated to a real network address (e.g., IPv4 or IPv6 addresses) and the packet payload is encrypted. Outgoing packets that are addressed directly to real network addresses pass through in a conventional manner.