Types of MAC address entries

A MAC address table can contain the following types of entries:

• Static entries—A static entry is manually added to forward frames with a specific destination MAC address out of the associated interface, and it never ages out. A static entry has higher priority than a dynamically learned one.

• Dynamic entries—A dynamic entry can be manually configured or dynamically learned to forward frames with a specific destination MAC address out of the associated interface. A dynamic entry might age out. A manually configured dynamic entry has the same priority as a dynamically learned one.

• Blackhole entries—A blackhole entry is manually configured and never ages out. A blackhole entry is configured for filtering out frames with a specific source or destination MAC address. For example, for security purposes, to block all frames destined for or sourced from a user, you can configure the user's MAC address as a blackhole MAC address entry.

• Multiport unicast entries—A multiport unicast entry is manually added to send frames with a specific unicast destination MAC address out of multiple ports, and it never ages out. A multiport unicast entry has higher priority than a dynamically learned one.

A static, blackhole, or multiport unicast MAC address entry can overwrite a dynamic MAC address entry, but not vice versa.