A method for discovering a link between an entry-exit device of a computer network and a customer edge device is disclosed. The customer edge device includes an address and the entry/exit point device includes a routing table. Interfaces with the routing table and addresses of the computer network related to the entry/exit point device are obtained. Either a routing protocol or the routing table is used to obtain routing information. The routing information is compared to a selected address to find a match. The routing information the matches the selected address represents the address of the customer edge device.