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Cisco Bug: CSCvv82819 - Manually configured MAC address is programmed in hardware when interface is admin down

Last Modified

Oct 14, 2020

Products (1)

  • Cisco Catalyst 9600 Series Switches

Known Affected Releases

17.3.1

Description (partial)

Symptom:
A Catalyst 9k switch may install a static mac address entry for the SVI hw and/or bia address despite the SVI being admin-down. 

In this scenario, with no active L3 interface we would expect the mac not to be installed until the SVI is brought online and becomes active. This static entry caused the mac to not be learned dynamically if it lives elsewhere in the network.

Conditions:
First seen on Cat9600 switches running 17.3.1, this may also be seen on other Cat9k series switches and impacts 16.12.4 as well.

To run into this, you must have a user defined mac address configured on the SVI and either configure the mac after the interface is admin down, or reload the switch with this config already in place.
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