Hello, we recently installed a new core switch (cisco C9407R) at one of our schools and I keep getting these MAC Flapping messages.
*Jan 24 15:06:47.069: %SW_MATM-4-MACFLAP_NOTIF: Host 1a82.cee1.c718 in vlan 20 is flapping between port Te3/0/3 and port Te5/0/29
*Jan 24 15:07:30.815: %SW_MATM-4-MACFLAP_NOTIF: Host 8a8f.586d.c6a3 in vlan 20 is flapping between port Te5/0/32 and port Te3/0/3
*Jan 24 15:07:47.194: %SW_MATM-4-MACFLAP_NOTIF: Host f211.4ec4.e985 in vlan 20 is flapping between port Te3/0/1 and port Te3/0/3
I know that this is usually because of a loop or that the switch sees the same MAC addresses on 2 different ports. We still have the old core switch connected because we did not have the correct SFP transceivers for all of the switches to connect to the new one. The old one is connected to the new one via ethernet and not fiber.
Here are the port configurations for the flapping ports:
AP's
interface TenGigabitEthernet5/0/25
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/26
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/27
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/28
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/29
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/30
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/31
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/32
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/33
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/34
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/35
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/36
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/37
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/38
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/39
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/40
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/41
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/42
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/43
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/44
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/45
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/46
switchport trunk native vlan 45
switchport mode trunk
!
interface TenGigabitEthernet5/0/47
switchport mode trunk
Switches:
interface TenGigabitEthernet3/0/1
switchport mode trunk
!
interface TenGigabitEthernet3/0/2
switchport mode trunk
!
interface TenGigabitEthernet3/0/3
switchport mode trunk
!
interface TenGigabitEthernet3/0/4
switchport mode trunk
Any help would be greatly appreciated.
