Control over the movement of packets is exercised by edge nodes of a network mapping the addresses of incoming packets in accordance with a prespecified functional mapping P. Remote sources of packets are provided address information that is mapped with a prespecified functional mapping Q, where mappings P and Q are such that P(Q(j)=j. The mapping change at regular intervals, or upon the occurrence of specified events, and with each change, the communicating the remote source is provided with a different mapped address to be used.