Multi-port network communication device with selective mac address filtering

A multi-port network switch including:

• a plurality of ports for the reception and transmission of addressed data packets which include media access control source and destination address data;
• a forwarding database relating media access control addresses to said ports;
• a forwarding mechanism for directing, in response to media access control destination address data in a received packet and in cooperation with said forwarding database, said received packet to at least one of the plurality of ports,
• a memory for the selectively controllable storage of permitted media access control addresses, and
• means for restricting forwarding of packets from the device in response to an examination of media access control data in said packets and said permitted media access control addresses,
• wherein said means for restricting prevents the forwarding of said received packet when said packet is a received unicast packet having a source address and a destination address when neither of those addresses in the received unicast packet corresponds to a permitted media access control address, said device including means for comparing both the source address and the destination address of said received unicast packet with said permitted media access control addresses