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Verifying That Persistent MAC Learning Is Working Correctly

Purpose

Verify that persistent MAC learning, also known as sticky MAC, is working on the interface. Persistent MAC learning allows retention of dynamically learned MAC addresses on an interface across restarts of the switch (or if the interface goes down).

Action

Display the MAC addresses that have been learned. The following sample output shows the results when persistent MAC learning is enabled on interface ge-0/0/42:

show ethernet-switching table persistent-mac

user@switch> show ethernet-switching table

Ethernet-switching table: 8 entries, 2 learned, 5 persistent entries
  VLAN              MAC address       Type         Age Interfaces
  default           *                 Flood          - All-members
  default           00:10:94:00:00:02 Persistent        0 ge-0/0/42.0
  default           00:10:94:00:00:03 Persistent        0 ge-0/0/42.0
  default           00:10:94:00:00:04 Persistent        0 ge-0/0/42.0
  default           00:10:94:00:00:05 Persistent        0 ge-0/0/42.0
  default           00:10:94:00:00:06 Persistent        0 ge-0/0/42.0
  default           00:21:59:c8:0c:50 Learn             0 ae0.0
  default           02:21:59:c8:0c:44 Learn             0 ae0.0

Meaning

The sample output shows that learned MAC addresses are stored in the Ethernet switching table as persistent entries. If the switch is rebooted or the interface goes down and comes back up, these addresses will be restored to the table.