Abstract: A method and means for automatically detecting, for any site or LAN of an organizational net, all the external subnets within the net with which it, or any subnet within it, actively communicate through a WAN and compiling a configuration- or mapping table that lists address pairs of such detected subnets as corresponding active tunnels. The process, carried out by a special agent, includes intercepting data packets flowing in- or out of the LAN and extracting from each the local and remote subnet addresses. Further the table is to indicate, for each such tunnel, an IP address associated with the LAN to which the remote subnet is connected. Such an address is obtained by sending in inquiry message to the remote subnet, which is intercepted by the corresponding remote agent, and having the remote agent send a response message to the originating agent, from which the remote agent's address is extracted. Other data may also be exchanged between the agents in the net, including data in the compiled tables.