On Mon, Sep 21, 2020 at 12:21:35PM -0500, Todd Mueller wrote:
>Could someone please check the MICE port for Velocity Telephone, I saw it go
>down about 15 minutes ago.
>
>I suspect it shut down because there was more than 1 MAC address coming in.
>I noticed the MAC address for a layer 2 interface from one of our switches
>showing up in the corresponding VLAN momentarily for some reason, but it is
>gone now.

Yes, it was a MAC address security violation. I assume it'll be fine
to post it, so you can find what one is causing you grief.

Sep 21 12:02:46 core-sw0 PortSec: %PORTSECURITY-2-PSECURE_VIOLATION: Security violation occurred, caused by MAC address 64:9e:f3:ec:b9:73 on vlan 1 interface Ethernet4/21.
Sep 21 12:02:46 core-sw0 Ebra: %ETH-4-ERRDISABLE: portsec error detected on Ethernet4/21.
Sep 21 12:02:46 core-sw0 Ebra: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet4/21 (15250 - Velocity Telephone), changed state to down
Sep 21 12:02:46 core-sw0 Stp: %SPANTREE-6-INTERFACE_DEL: Interface Ethernet4/21 has been removed from instance Vl1

I cleared the error from the port.