Mac Address Flapping

[ranjit123]

Dear All,

We are facing a strange problem that the mac-address-table address 02:01:00:00:00:00 is flapping and belonging to more than one machine, because of which the core CPU switch utilization is increasing a lot. As there are access switches connected to the core switch.

please find the details as below

====================================================================

switch#sh mac-address-table address 0201.0000.0000
           Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
    1    0201.0000.0000    DYNAMIC     Fa0/8

ip address <*.*.*.*>

switch#sh mac-address-table address 02:01:00:00:00:00
           Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
    2    0201.0000.0000    DYNAMIC     Fa0/7
    6    0201.0000.0000    DYNAMIC     Gi0/1

==============================================================

Kindly check the same and advise.

Regads,

Ranjit.

[Aaron Harrison]

Hi

There are lots of refences to this on google - it appears that it could be a Windows load balancing related thing:

http://www.google.co.uk/search?q=0201.0000.0000&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

I would start by seeing what hosts are on the ports that are seeing the MAC address (obviously if they're trunks to the access switches, check on the access switches and see which edge ports have the MAC). Once you know what hosts are generating the data, find out why..

Aaron

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[Ganesh Hariharan · Accepted solution]

Dear All,

We are facing a strange problem that the mac-address-table
address 02:01:00:00:00:00 is flapping and belonging to more than one
machine, because of which the core CPU switch utilization is increasing
a lot. As there are access switches connected to the core switch.
please find the details as below
====================================================================
switch#sh mac-address-table address 0201.0000.0000
           Mac Address Table
 -------------------------------------------
Vlan    Mac Address       Type        Ports
 ----    -----------       --------    -----
    1    0201.0000.0000    DYNAMIC     Fa0/8
ip address <*.*.*.*>
 
switch#sh mac-address-table address 02:01:00:00:00:00
           Mac Address Table
 -------------------------------------------
Vlan    Mac Address       Type        Ports
 ----    -----------       --------    -----
    2    0201.0000.0000    DYNAMIC     Fa0/7
    6    0201.0000.0000    DYNAMIC     Gi0/1
==============================================================
Kindly check the same and advise.
Regads,
Ranjit.

Hi Ranjit,

Host flapping and mac-address flapping can be from server or host end at nic level configuration of teaming (load balancing feature) just check it out the Teaming configuration at server or host level is active/passive and then check the behavior.

Hope to help !!

Ganesh.H

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