Secure communication with mobile hosts

DETAILED DESCRIPTION Briefly stated, the present invention involves a method for secure data communication between an inside network 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.
When packets are received by the gateway from the inside network, and are addressed to a secure address, then the secure address is replaced by the corresponding network address and the packet is encrypted and authenticated.
As used herein, the term "securing a packet" means authentication and/or encryption--and not necessarily encryption only.
In this manner, bidirectional secure communications are supported.