display mac-address blackhole

Function

The display mac-address blackhole command displays blackhole MAC address entries.

Format

display mac-address blackhole [ vlan vlan-id | vsi vsi-name ] [ verbose ]

Parameters

Parameter	Description	Value
vlan vlan-id	Displays blackhole MAC address entries in a specified VLAN.	The value is an integer that ranges from 1 to 4094.
vsi vsi-name	Displays blackhole MAC address entries of a specified virtual switch instance (VSI). vsi-name specifies the name of a VSI. NOTE: Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731S-H, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730S-H, and S6730-H support this parameter.	The value is a string of 1 to 31 case-sensitive characters, spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string.
verbose	Displays detailed information about blackhole MAC address entries.	-

Views

All views

Default Level

1: Monitoring level

Usage Guidelines

Usage Scenario

The MAC address table of the switch stores MAC addresses of other devices. When forwarding an Ethernet frame, the switch searches the MAC address table for the outbound interface according to the destination MAC address and VLAN ID in the Ethernet frame.

The MAC address table contains the following MAC address entries:

Blackhole MAC address entries that are used to discard packets with the specified MAC addresses or destination MAC addresses. Blackhole MAC address entries are manually configured and will not be aged out.
Static MAC entries that are manually configured and will not be aged out.
Dynamic MAC address entries that are learned by the switch and will be aged out when the aging time expires.

To check whether blackhole MAC address entries are configured correctly, run this command. These entries ensure communication between authorized users.

Follow-up Procedure

If any blackhole MAC address entry in the command output is incorrect, run the undo mac-address command to delete the entry or run the mac-address blackhole command to add a correct one.

Precautions

If you run the display mac-address blackhole command without parameters, all blackhole MAC address entries are displayed.
If the MAC address table does not contain any blackhole MAC address, no information is displayed.

Example

# Display all blackhole MAC address entries.

<HUAWEI> display mac-address blackhole
------------------------------------------------------------------------------- 
MAC Address          VLAN/VSI/BD                Learned-From         Type       
-------------------------------------------------------------------------------
0022-0022-0033       100/-/-                    -                   blackhole 
0000-0000-0001       200/-/-                    -                   blackhole 

-------------------------------------------------------------------------------
Total items displayed = 2

# Display blackhole MAC address entries in VLAN 100.

<HUAWEI> display mac-address blackhole vlan 100
------------------------------------------------------------------------------- 
MAC Address          VLAN/VSI/BD                 Learned-From        Type       
-------------------------------------------------------------------------------
0022-0022-0033       100/-/-                      -                  blackhole 
0000-0000-0001       100/-/-                      -                  blackhole 

-------------------------------------------------------------------------------
Total items displayed = 2

**Table 1** Description of the display mac-address blackhole command output
Item	Description
MAC Address	Destination MAC address in a blackhole MAC address entry.
VLAN/VSI/BD	ID of the VLAN, name of the VSI, or ID of the BD that a MAC address belongs to.
Learned-From	When the type of a MAC address entry is blackhole, "-" is displayed.
Type	Type of a MAC address entry. blackhole: indicates a blackhole MAC address entry, which is manually configured and will not be aged out, configured by using the mac-address blackhole command.