03-10-2017 06:11 AM - edited 03-08-2019 09:41 AM
Dear all,
Please if you can helpme undertand, what could cause this problem, and what I have to do to investigate a solution.
It only happened once for a short time.
Please if you need more background do not hesitate to ask
Thanks
Best regards.
Samuel Domb
Log Buffer (4096 bytes):
00.1b01 in vlan 27 is flapping between port Gi0/41 and port Gi0/40
001349: Mar 9 16:43:34: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1a01 in vlan 2
6 is flapping between port Gi0/40 and port Gi0/46
001350: Mar 9 16:43:36: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1c01 in vlan 2
8 is flapping between port Gi0/40 and port Gi0/41
001351: Mar 9 16:43:36: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1502 in vlan 2
1 is flapping between port Gi0/40 and port Gi0/41
001352: Mar 9 16:43:36: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1b02 in vlan 2
7 is flapping between port Gi0/41 and port Gi0/40
001353: Mar 9 16:43:37: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1402 in vlan 2
0 is flapping between port Gi0/46 and port Gi0/40
001354: Mar 9 16:43:44: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1501 in vlan 2
1 is flapping between port Gi0/40 and port Gi0/41
001355: Mar 9 16:43:45: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1802 in vlan 2
4 is flapping between port Gi0/46 and port Gi0/40
001356: Mar 9 16:43:46: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1602 in vlan 2
2 is flapping between port Gi0/46 and port Gi0/40
001357: Mar 9 16:43:46: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1902 in vlan 2
5 is flapping between port Gi0/41 and port Gi0/40
001358: Mar 9 16:43:46: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1a01 in vlan 2
6 is flapping between port Gi0/46 and port Gi0/40
001359: Mar 9 16:43:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1502 in vlan 2
1 is flapping between port Gi0/40 and port Gi0/41
001360: Mar 9 16:43:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1702 in vlan 2
3 is flapping between port Gi0/40 and port Gi0/41
001361: Mar 9 16:43:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1901 in vlan 2
5 is flapping between port Gi0/40 and port Gi0/41
001362: Mar 9 16:43:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1b02 in vlan 2
7 is flapping between port Gi0/41 and port Gi0/40
001363: Mar 9 16:43:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1601 in vlan 2
2 is flapping between port Gi0/46 and port Gi0/40
001364: Mar 9 16:43:48: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1401 in vlan 2
0 is flapping between port Gi0/40 and port Gi0/46
001365: Mar 9 16:43:48: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1402 in vlan 2
0 is flapping between port Gi0/46 and port Gi0/40
001366: Mar 9 16:43:48: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1a02 in vlan 2
6 is flapping between port Gi0/40 and port Gi0/46
001367: Mar 9 16:43:53: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1b01 in vlan 2
7 is flapping between port Gi0/40 and port Gi0/41
001368: Mar 9 16:43:58: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1b02 in vlan 2
7 is flapping between port Gi0/40 and port Gi0/41
001369: Mar 9 16:43:59: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1a02 in vlan 2
6 is flapping between port Gi0/46 and port Gi0/40
001370: Mar 9 16:44:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1802 in vlan 2
4 is flapping between port Gi0/46 and port Gi0/40
001371: Mar 9 16:44:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1501 in vlan 2
1 is flapping between port Gi0/40 and port Gi0/41
001372: Mar 9 16:44:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1401 in vlan 2
0 is flapping between port Gi0/46 and port Gi0/40
001373: Mar 9 16:44:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1402 in vlan 2
0 is flapping between port Gi0/40 and port Gi0/46
001374: Mar 9 16:44:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1701 in vlan 2
3 is flapping between port Gi0/41 and port Gi0/40
001375: Mar 9 16:44:02: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1902 in vlan 2
5 is flapping between port Gi0/41 and port Gi0/40
001376: Mar 9 16:44:03: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1502 in vlan 2
1 is flapping between port Gi0/40 and port Gi0/41
001377: Mar 9 16:44:04: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1c01 in vlan 2
8 is flapping between port Gi0/41 and port Gi0/40
001378: Mar 9 16:44:04: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1c02 in vlan 2
8 is flapping between port Gi0/40 and port Gi0/41
001379: Mar 9 16:44:04: %SW_MATM-4-MACFLAP_NOTIF: Host 0007.b400.1602 in vlan 2
2 is flapping between port Gi0/46 and port Gi0/40
XCL_SW_CISCO2#
03-10-2017 06:40 AM
What are the ports mentioned in the logs doing?
What is plugged into them?
The most common cause of MAC flaps is when users roam between Wireless AP's but it could also mean a L2 switching loop.
03-10-2017 07:04 AM
03-12-2017 04:32 AM
Hi,
Based on the switch logs , the end device is flapping between two ports ...do the end device is configured with some software like teaming with Active/Active configuration. If yes , Try configuring the end device with Active/Passive configuration and see the behaviour.
Hope it Helps..
-GI
03-13-2017 08:17 AM
Hi, Thanks.
The two switches are connected to two routers in a GLBP configuration.
Regards.
03-13-2017 08:25 AM
Thanks Samuel, do you know if the MACs are associated to any end user device?
show mac address-table | inc MAC-Address
show ip arp
I saw many MAC addresses on your output. Also verify if your STP is configured properly.
03-13-2017 08:29 AM
Hi Julio,
Those mac address 0008.b400.xxxx are mac address from the GLBP configuration in a router atacched to the f40 port of the switch.
The router is configured as a router on a stick configuration.
here the GLBP output:
GW1_XCL#sh glbp summ
GW1_XCL#sh glbp br
GW1_XCL#sh glbp brief
Interface Grp Fwd Pri State Address Active router Standby router
Gi0/0.20 20 - 150 Active 192.168.20.1 local 192.168.20.19
Gi0/0.20 20 1 - Listen 0007.b400.1401 192.168.20.19 -
Gi0/0.20 20 2 - Active 0007.b400.1402 local -
Gi0/0.21 21 - 130 Standby 192.168.21.1 192.168.21.19 local
Gi0/0.21 21 1 - Active 0007.b400.1501 local -
Gi0/0.21 21 2 - Listen 0007.b400.1502 192.168.21.19 -
Gi0/0.22 22 - 150 Active 192.168.22.1 local 192.168.22.19
Gi0/0.22 22 1 - Listen 0007.b400.1601 192.168.22.19 -
Gi0/0.22 22 2 - Active 0007.b400.1602 local -
Gi0/0.23 23 - 130 Standby 192.168.23.1 192.168.23.19 local
Gi0/0.23 23 1 - Active 0007.b400.1701 local -
Gi0/0.23 23 2 - Listen 0007.b400.1702 192.168.23.19 -
Gi0/0.24 24 - 150 Active 192.168.24.1 local 192.168.24.19
Gi0/0.24 24 1 - Listen 0007.b400.1801 192.168.24.19 -
Gi0/0.24 24 2 - Active 0007.b400.1802 local -
Gi0/0.25 25 - 130 Standby 192.168.25.1 192.168.25.19 local
Gi0/0.25 25 1 - Active 0007.b400.1901 local -
Gi0/0.25 25 2 - Listen 0007.b400.1902 192.168.25.19 -
Gi0/0.26 26 - 150 Active 192.168.26.1 local 192.168.26.19
Gi0/0.26 26 1 - Listen 0007.b400.1a01 192.168.26.19 -
Gi0/0.26 26 2 - Active 0007.b400.1a02 local -
Gi0/0.27 27 - 130 Standby 192.168.27.1 192.168.27.19 local
Gi0/0.27 27 1 - Active 0007.b400.1b01 local -
Gi0/0.27 27 2 - Listen 0007.b400.1b02 192.168.27.19 -
Gi0/0.28 28 - 130 Standby 192.168.28.1 192.168.28.19 local
Gi0/0.28 28 1 - Active 0007.b400.1c01 local -
Gi0/0.28 28 2 - Listen 0007.b400.1c02 192.168.28.19 -
Gi0/0.40 40 - 150 Active 192.168.40.1 local unknown
Gi0/0.40 40 1 - Active 0007.b400.2801 local -
GW1_XCL#
Regards
03-13-2017 08:45 AM
Thanks
I think there are MAC addresses are used by GLBP for all the platforms, verify the MAC used:
sh glbp brief
https://supportforums.cisco.com/discussion/10559406/4-virtual-mac-addresses-glbp
03-13-2017 09:03 AM
Julio,
That's what I have already sent.
Regards.
03-12-2017 06:29 AM
Hi
Please verify this link, it could be related to a loop, You should identify the devices related to that MAC Addresses:
https://blogs.it.ox.ac.uk/networks/2011/02/04/mac-flaps-why-are-they-bad/
Hope it is useful.
:-)
03-13-2017 08:25 AM
Thanks,
Those MAC addess came from a router configuration in glbp mode.
Regards
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