Abstract: An arrangement for selective filtering, e.g. one-way filtering, of messages received by a 2-port bridge from stations connected to two LANs of an extended LAN is provided. The bridge includes a message filtering database containing the addresses of all stations connected to one of the LANs. The database also contains a list of higher-level protocols employed by the stations. Associated with each protocol-type is information used by the bridge to dispose of the message. The message filtering database comprises a single table memory capable of supporting both ports of the bridge. The selective filtering process involves a two-step analysis by the bridge to determine whether to discard the message or forward it to another port. The analysis is based on a destination address and a protocol-type of the received message.