Abstract: A method for managing frames in a global-area communications network comprises a plurality of sub-networks linked to one another by tunnels at the ends of which there are tunnel endpoints, at least one of the sub-networks comprising at least one source device connected to one of said tunnel endpoints through said sub-network. When a given tunnel endpoint receives from a local sub-network, to which said given tunnel endpoint is connected, a frame sent out by a source device in the global-area network, the given tunnel endpoint performs the following steps: obtaining, from said frame, an address of the source device; verifying that the obtained address is included in a first list of addresses comprising addresses associated with source devices connected to remote sub-network or sub-networks distinct from the local sub-network; and in the event of positive verification, discarding said frame.