4-29
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 4 Administering the Switch Managing the MAC Address Table
If you add a unicast MAC address as a static address and configure unicast MAC address filtering,
the switch either adds the MAC address as a static address or drops packets with that MAC address,
depending on which command was entered last. The second command that you entered overrides
the first command.
For example, if you enter the mac address-table static vlan interface global configuration
command followed by the mac address-table static vlan drop command, the switch drops packets
with the specified MAC address as a source or destination.
If you enter the mac address-table static vlan drop global configuration command followed by the
mac address-table static vlan interface command, the switch adds the MAC address as a static
address.
You enable unicast MAC address filtering and configure the switch to drop packets with a specific
address by specifying the source or destination unicast MAC address and the VLAN from which it is
received.
To configure the switch to drop a source or destination unicast static address, perform this task:
This example shows how to enable unicast MAC address filtering and to configure the switch to drop
packets that have a source or destination address of c2f3.220a.12f4. When a packet is received in
VLAN 4 with this MAC address as its source or destination, the packet is dropped:
Switch# configure terminal
Switch(config)# mac address-table static c2f3.220a.12f4 vlan 4 drop
Switch(config)# end
Switch#
Note To filter MAC addresses on a secondary VLAN, specify the corresponding primary VLAN in the above
configuration. If the specified VLAN is a primary VLAN, all matching packets received in this primary
VLAN and associated secondary VLANs are dropped.
Command Purpose
Step 1 configure terminal Enters global configuration mode.
Step 2 mac address-table static mac-addr
vlan vlan-id drop Enables unicast MAC address filtering and configure the switch to drop a
packet with the specified source or destination unicast static address.
For mac-addr, specify a source or destination unicast MAC address.
Packets with this MAC address are dropped.
For vlan-id, specify the VLAN for which the packet with the
specified MAC address is received. Valid VLAN IDs are 1 to 4094.
To disable unicast MAC address filtering, use the no mac address-table
static vlan global configuration command.
Step 3 end Returns to privileged EXEC mode.
Step 4 show mac address-table static Verifies your entries.
Step 5 copy running-config startup-config (Optional) Saves your entries in the configuration file.