3.3. MAC Address Table Commands

Command Purpose

Use the mac-address-table aging-time Global Config command on the switch to set the length of time that a dynamic entry remains in the MAC address table after the entry is used or updated. Use the no form of this command to return to the default setting. The aging time applies to all VLANs.

Prerequisites

Command Syntax

mac_address-table aging-time SECONDS

no mac_address-table aging-time

Command Mode

Global Config

Default

The default is 300 seconds

Usage

If packets are not received continuously, user can increase the aging time to make the system recording the dynamic entries for a longer time. Increasing the time can reduce the possibility of flooding when the hosts send again.

Examples

This example shows how to set the aging time to 200 seconds for all VLANs:

Switch# configure terminal
Switch(config)# mac-address-table aging-time 200

Related Commands

show mac address-table aging-time

Command Purpose

Use the mac-address-table hardware-learning enable Global Config command on the switch to study FDB without software. Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

mac_address-table hardware-learning enable

no mac_address-table hardware-learning enable

Command Mode

Global Config

Default

Disable

Usage

Hardware learning is more faster than software learning.

Examples

This example shows how to enable hardware learning:

Switch# configure terminal
Switch(config)# mac-address-table hardware-learning enable

Related Commands

None

Command Purpose

Use the mac-address-table forward Global Config command on the switch to add static addresses to the MAC address table. Use the no form of this command to remove static entries from the table.

Prerequisites

Command Syntax

mac_address-table MAC_ADDR forward ( IFNAME | eps EPS_ID | remote-vtep REMOTE_VTEP_ID | smart-link SMART_LINK_ID ) vlan VLAN_ID

no mac_address-table MAC_ADDR forward ( IFNAME | eps EPS_ID | remote-vtep REMOTE_VTEP_ID | smart-link SMART_LINK_ID ) vlan VLAN_ID

Command Mode

Global Config

Default

None

Usage

The static address entries which are added by this command are not aged.

Examples

This example shows how to add the static address c2f3220a12f4 to the MAC address table When a packet is received in VLAN 4 with this MAC address as its destination, the packet is forwarded to the specified interface:

Switch# configure terminal
Switch(config)# mac-address-table c2f3.220a.12f4 forward eth-0-1 vlan 4

Related Commands

show mac address-table

Command Purpose

Use the mac-address-table discard Global Config command on the switch to enable unicast MAC address filtering and to configure the switch to drop traffic with a specific source or destination MAC address. Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

mac_address-table MAC_ADDR discard

no mac_address-table MAC_ADDR discard

Command Mode

Global Config

Default

None

Usage

Follow these guidelines when using this feature:

Multicast MAC addresses, broadcast MAC addresses, and router MAC addresses are not supported. Packets that are forwarded to the CPU are also not supported.

Examples

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 c2f3220a12f4 When a packet is received with this MAC address as its source or destination, the packet is dropped:

Switch# configure terminal
Switch(config)# mac-address-table c2f3.220a.12f4 discard

Related Commands

mac-address-table forward

Command Purpose

Use the clear mac address-table privileged EXEC command on the switch to delete all dynamic(or static, or multicast) addresses, or all dynamic(or static, or multicast) addresses on a particular interface, or all dynamic(or static, or multicast) addresses on a particular VLAN from the MAC address table.

Prerequisites

Command Syntax

clear mac address-table ( static | dynamic | multicast ) { address MAC_ADDR | interface IFNAME | vlan VLAN_ID }

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This example shows how to remove a specific MAC address from the dynamic address table:

Switch# clear mac address-table dynamic address 0058.3f70.0007

Related Commands

show mac address-table

Command Purpose

Use this command to support to forward packets with the src-mac and dset-mac learned by the same port.

Prerequisites

Command Syntax

switchport port-bridge enable

no switchport port-bridge enable

Command Mode

Interface Configuration

Default

None

Usage

None

Examples

This example shows how to enable port-bridge function:

Switch# configure terminal
Switch(config)# interface eth-0-1
Switch(config-if)# no switchport port-bridge enable

Related Commands

None

Command Purpose

Use the show mac address-table aging-time privileged EXEC command to display the aging time of all address table instances on all VLANs.

Prerequisites

Command Syntax

show mac address-table aging-time

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table aging-time command:

Switch# show mac address-table aging-time

MAC address table aging time is 300 seconds

Related Commands

mac-address-table aging-time

Command Purpose

Use the show mac address-table privileged EXEC command to display a specific MAC address table static and dynamic entry or the MAC address table static and dynamic entries on a specific interface or VLAN.

Prerequisites

Command Syntax

show mac address-table ( dynamic | static | multicast | ) ( address MAC_ADDR | interface IFNAME | vlan VLAN_ID | )

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table command:

Switch# show mac address-table

Mac Address Table
------------------------------------------------
(*) - Security Entry (M) - MLAG Entry
(MO) - MLAG Output Entry (MI) - MLAG Input Entry
Vlan Mac Address Type Ports
---- ----------  ---- -----
1 0000.0000.0001 static eth-0-2
1 0000.0001.0003 static(\*) eth-0-1
1 0000.0001.0002 static(\*) eth-0-1
2 26fc.72e5.0100 dynamic(\*) eth-0-9
1 0100.0000.0001 static eth-0-2

Related Commands

mac-address-table

Command Purpose

Use the show mac address-table hardware privileged EXEC command to display a specific MAC address table static and dynamic entry or the MAC address table static and dynamic entries on a specific interface or VLAN in hardware.

Prerequisites

Command Syntax

show mac address-table hardware ( dynamic | static | ) ( address MAC_ADDR | interface IFNAME | vlan VLAN_ID | )

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table hardware command:

Switch# show mac address-table hardware

Mac Address Table
-------------------------------------
(*) - Security Entry (M) - MLAG Entry
(MO) - MLAG Output Entry (MI) - MLAG Input Entry
Vlan Mac Address Type Ports
---- ----------- ---- -----
1 0000.0000.0001 static eth-0-2
1 0000.0001.0003 static(\*) eth-0-1
1 0000.0001.0002 static(\*) eth-0-1
2 26fc.72e5.0100 dynamic(\*) eth-0-9
1 0100.0000.0001 static eth-0-2

Related Commands

mac-address-table

Command Purpose

Use the show mac address-table count privileged EXEC command to display the number of addresses present in all VLANs.

Prerequisites

Command Syntax

show mac address-table count

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table count command:

Switch# show mac address-table count

Dynamic Address Count : 0 (Security: 0)
Static Address Count : 0 (Security: 0)
Blackhole Address Count: 1
Total Mac Addresses : 1 (Security: 0)

Related Commands

show mac address-table

Command Purpose

Use the show mac address-table count privileged EXEC command to display the number of addresses present in all VLANs in hardware.

Prerequisites

Command Syntax

show mac address-table hardware count

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table hardware count command:

Switch# show mac address-table hardware count

MAC address count in hardware table:
(Include MAC security entry)
--------------------------------------------
Dynamic Address Count : 0
Static Address Count : 0
Total Mac Addresses : 0

Related Commands

show mac address-table hardware

Command Purpose

Use the show mac address-table add-fdb-fail privileged EXEC command to display all failed static FDB entries when adding FDB table in chip for hash conflict.

Prerequisites

Command Syntax

show mac address-table add-fdb-fail

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table add-fdb-fail command:

Switch# show mac address-table add-fdb-fail

Vlan Mac Address Type Ports
----------------------------------------------
1 0000.0000.0001 static eth-0-1
1 0000.0000.0002 static eth-0-2

Related Commands

show mac address-table

Command Purpose

Use the show mac-filter address-table privileged EXEC command to display the number of filter addresses present in all VLANs.

Prerequisites

Command Syntax

show mac-filter address-table

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac-filter address-table command:

Switch# show mac-filter address-table

MAC Filter Address Table
-----------------------------------
Current count : 0
Max count : 128
Left count : 128
Filter address list :
-----------------------------------

Related Commands

show mac address-table

Command Purpose

Use this command to display the resource statistic used by mac-filter.

Prerequisites

Command Syntax

show resource mac-filter

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

The following is sample output from the show resource mac-filter command:

Switch# show resource mac-filter

MAC-FILTER
Resource Used Capability
=============================================================
Blackhole MAC Addresses 0 128

Related Commands

show resource static-fdb

Command Purpose

Use this command to display the resource statistic used by static FDB.

Prerequisites

Command Syntax

show resource static-fdb

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

The following is sample output from the show resource static-fdb command:

Switch# show resource static-fdb

STATIC-FDB
Resource Used Capability
=============================================================
Static FDB 0 1024

Related Commands

show resource mac-filter

Command Purpose

Use the mac-address-table discard configuration command on the switch to enable unicast MAC address filtering and to configure the switch to drop traffic with a specific source or destination MAC address and VLAN matches. Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

mac_address-table MAC_ADDR discard ( vlan VLAN_ID | )

Command Mode

Global Config

Default

None

Usage

Follow these guidelines when using this feature:

Multicast MAC addresses, broadcast MAC addresses, and router MAC addresses are not supported. Packets that are forwarded to the CPU are also not supported.Designed VLAN should be created in advance.

Examples

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 c2f3220a12f4 When a packet is received with this MAC address as its source or destination, the packet is dropped:

Switch# configure terminal
Switch(config)# vlan 2
Switch(config-vlan)#exit
Switch(config)# mac-address-table c2f3.220a.12f4 discard vlan 2

Related Commands

mac-address-table forward

Command Purpose

Use the clear mac address-table privileged EXEC command on the switch to delete all designed blackhole addresses on a particular VLAN from the MAC address table.

Prerequisites

Command Syntax

clear mac address-table blackhole ( vlan VLAN_ID | )

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This example shows how to remove a specific VLAN from the blackhole address table:

Switch# clear mac address-table blackhole vlan 2

Related Commands

show mac address-table

Command Purpose

Use the show mac address-table privileged EXEC command to display a specific MAC address table blackhole entry on a specific VLAN.

Prerequisites

Command Syntax

show mac address-table blackhole ( vlan VLAN_ID | )

Command Mode

Privileged EXEC

Default

None

Usage

None

Examples

This is an example of output from the show mac address-table blackhole command:

Switch# show mac address-table blackhole

Mac Address Table
-------------------------------------
(*) - Security Entry (M) - MLAG Entry
(MO) - MLAG Output Entry (MI) - MLAG Input Entry
(E) - EVPN Entry (EO) - EVPN Output Entry
(EI) - EVPN Input Entry
Vlan Mac Address Type Ports
---- ----------- ---- -----
2 0000.0000.0001 blackhole drop

Related Commands

mac-address-table