To permit communications between devices using different communication protocols, a mapping device is connected to one or more communication networks, and stores associations between communication addresses as dynamic address mappings. A dynamic address mapping is associated with an initiator address (from which the communication is initiated) and a recipient address (to which a communication is initially addressed) and minimally contains a final address (to which a communication is finally routed). A new dynamic address mapping can be created in response a request, typically from a communication initiator. Communications from the initiator address to the recipient address are routed to the final address, with appropriate format conversion if the protocol of the final address is differentto that of the initiator address. A reply address may also be stored in a dynamic address mapping for return communications, and a reply mapping may be automatically generated to map the reply address to the initiator address.