Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
Community Member

HSRP error

Can anyone guide me with this error please...

4w5d: %C4K_EBM-4-HOSTFLAPPING: Host 00:19:06:14:20:BF in vlan 40 is flapping bet

ween port Gi6/40 and port Po1

4w5d: %HSRP-4-DUPADDR: Duplicate address on Vlan40, sourced by 0019.



Re: HSRP error


Both the messages points towards a possible network loop...

%C4K_EBM-4-HOSTFLAPPING: Host [mac-addr] in vlan [dec] is flapping between port [char] and port [char]

The specified host is detected as a source address on multiple ports. Typically, a host is supposed to be learned on only one port. A spanning tree loop is the most common cause of this condition. All traffic from the specified host is temporarily dropped. After 15 seconds, forwarding is reenabled. If the problem persists, the traffic from the problem host continues to be dropped indefinitely.

Recommended Action: Make sure that spanning tree is enabled to prevent spanning tree loops. If you have spanning tree disabled, make sure that you have no spanning tree loops in your network.

%HSRP-4-DUPADDR: Duplicate address [IP_address] on [chars], sourced by [enet]

The IP address in an HSRP message received on the specified interface is the same as the IP address of the router. Another router might be configured with the same IP address. The most likely cause is a network loop or a misconfigured switch that is causing the router to see its own HSRP Hello messages.

Recommended Action: Check the configurations on all the HSRP routers to ensure that the interface IP addresses are unique. Check that no network loops exist. If port channels are configured check that the switch is correctly configured for port-channels. Enable standby use-bia so that the error message displays the interface MAC address of the sending router. This can be used to determine if the error message is caused by a misconfigured router or a network loop.


Community Member

Re: HSRP error

Thanks for the quick reply.

Attached Physical topology diagram also the partial config

@ Access layer we got stack of 3com switches. The STP is disabled.

@ Distribution layer we have two 4506 A and B . A is root. All the ports are Desg FWD (Ether channel & Physical port for vlan )

On B Switch Port channel is Root fwd and the

Physical port for vlan is ALT Blocking

Can you please guide me where I have done the mistake... apart from those doggy 3com swicthes !!! which i dont have much control...

CreatePlease to create content