11-16-2006 12:49 PM - edited 03-05-2019 12:51 PM
Can anyone help me with this log, i think is a problem with spannig-tree but can anyone help me where the problem with comes from.
Nov 16 13:10:12: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 13:10:26: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Po1
Nov 16 13:10:42: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
11-16-2006 01:26 PM
Identify what you have connected on port 6/17 and 7/19. The switch thinks it's the same device because both ports are learning the same MAC Address (02:02:0A:00:07:93).
If it's the same device and it's configured for load balancing, you must configure load balancing at the switch as well.
Same goes for port 6/17 and Port-Channel1.
11-16-2006 02:14 PM
The deviceon the port 6/17 is a cisco 7204r and the other device is a cluster.
11-16-2006 01:28 PM
Hi ,
You can use the command show mac-address-table on switch to see mac address of ports.
The %C4K_EBM-4-HOSTFLAPPING:Host [mac-addr] in vlan [dec] is flapping between port [char] and port [char] error message signifies that the specified host is detected as a source address on multiple ports. Typically, a host is supposed to be learned on only one port.
These are common causes for this error message:
There is an spanning-tree loop.
All traffic from the specified host is temporarily dropped. After 15 seconds, forwarding is re-enabled. If the problem persists, the traffic from the problem host is dropped indefinitely. (However, in this case, expect the switch to see a few more MAC addresses on different VLANs.)
The host is connected to ports x/y, and x/y runs a type of clustering or redundancy and has an issue with this mechanism.
If the MAC address specified in the error message can be traced, this is likely the issue. For an example, refer to this error message:
%C4K_EBM-4-HOSTFLAPPING: Host 02:01:00:00:00:00 in vlan x is flapping between port Gi x/y and port Gi x/y
The MAC address 02:01:00:00:00:00 appears to be associated to Microsoft's Network Load Balancing (NLB) Service Heartbeat. It is suggested that the connected device (Microsoft host) be checked for causing these messages.
To resolve this problem, make sure that spanning tree is enabled. This prevents spanning tree loops. If spanning tree is disabled, make sure there are no spanning tree loops in the network.
To display spanning-tree state information for the VLAN ID mentioned in the error message, issue the show spanning-tree vlan vlan_id detail command and look for the last topology change.
If the MAC address in the error message is related to Microsoft Network Load Balancing (NLB), then you need to disable or clear the Network Load Balancing check box.
To disable NLB perform the procedure in Disabling Network Load Balancing (NLB).
Thanks,
satish
11-16-2006 01:42 PM
Are the ports in question connected to Wireless Access points? If it is, the user may be trying to connect to the network through different APs and from the switch perspective the host appears to be flapping between those ports.
HTH
Sundar
11-16-2006 02:19 PM
no, they are cluster and a router.
11-16-2006 02:18 PM
this is in one 4507r
Nov 16 11:38:55: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:39:25: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:39:56: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:40:26: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:40:56: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:41:25: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:41:56: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:42:25: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
Nov 16 11:42:56: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Po1 and port Gi7/19
and this is in another:
apping between port Gi6/17 and port Gi7/19
Nov 16 18:24:43: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:25:13: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:25:42: %C4K_EBM-4-HOSTFLAPPING: Host 00:11:43:12:AF:0B in vlan 4 is fl
apping between port Gi6/17 and port Gi4/1
Nov 16 18:25:43: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:26:13: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:26:27: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Po1
Nov 16 18:26:43: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:27:13: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:27:43: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
Nov 16 18:28:13: %C4K_EBM-4-HOSTFLAPPING: Host 02:02:0A:00:07:93 in vlan 4 is fl
apping between port Gi6/17 and port Gi7/19
both works as hsrp
11-16-2006 02:34 PM
Hi ,
Is it possible to disconnect and connect cable connecting to port G7/19.
Thanks,
satish
11-16-2006 02:59 PM
Are you doing bridging on the 7204r? i.e, is the interface to 4507 on the 7204r router configured with the bridge-group (#) command?
11-17-2006 04:55 AM
7204
interface FastEthernet0/0
ip address 10.0.4.39 255.255.252.0
duplex full
bridge-group 1
4507r
interface GigabitEthernet6/17
description Cisco7204vxr
switchport access vlan 4
switchport mode access
logging event link-status
speed 100
duplex full
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
11-17-2006 12:14 PM
Do you have spanning tree enabled on the 7204 or post the output of show spanning-tree 1. Also, post the output of show spanning-tree vlan 4 from the master switch of the cluster.
11-20-2006 04:26 AM
11-17-2006 04:49 AM
this is a cluster that i can not disconect.
01-22-2007 05:25 AM
Hey buddies,
Has anybody found a solution for this issue?
Ricardo ... have you found a solution?
I have exactly the same problem: same syslog messages and the both cores go down ... we have to reboot both cores in order to restablish the services.
It is very difficult to track the source of the problem.
Maybe this link could help many of you to make the tracking of a forwarding loop:
http://www.cisco.com/en/US/partner/tech/tk389/tk621/technologies_tech_note09186a0080136673.shtml
I am beginning to thinks that is a bug in IOS
:(
Regards
Pedro
01-22-2007 07:48 AM
hi Pedro
not, yet.
Aun tengo el problema desde ese tiempo para aca creo haber dado con una posible causa, el problema viene de servidores que utilizan NLB de Microsoft, por lo que he averiguado Microsoft recomienda no utlizar esta configuracion con equipos cisco, y por una pregunta que coloque en este forum cisco no tiene una solucion para ello. Indicame por favor si tus servidores utilizan tambien NLB.
Salduos
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