03-18-2008 01:09 AM - edited 03-03-2019 09:11 PM
we are seeing thie particular error message on our core and dist switch
%C4K_EBM-4-HOSTFLAPPING: Host 02:01:00:00:00:00 in vlan 101 is flapping between port Gi1/3 and port Gi1/45
Has anyone faces this before?
I got to know that the MAC is used by the Win server for load balancing.
-Sai.
03-18-2008 01:14 AM
Hi Sai
The %C4K_EBM-4-HOSTFLAPPING:Host [mac-addr] in vlan [dec] is flapping between port [char] and port [char] error message appears.
This error message appears on the switch when the switch detects the specified host address as a source address on multiple ports.
Basically the switch is seeing the same mac-address on 2 different ports. How are the NIC's on the W2k server set up ?
Jon
03-18-2008 01:20 AM
this are happening on ports connected to desktops running the Wins 2003 server OS.
Sai
03-18-2008 01:29 AM
Sai,
If the server is running the network loadbalancing service, you will get this message.
You can uninstall this service if this is not required
If you have done this for throughput, i would prefer doing LACP etherchannel which mostly works better than the MS loadbalancing
HTH
Narayan
03-18-2008 03:38 AM
In this case the MAC address was 02:01:00:00:00:00
The mac address in question is used by Windows 2003 Server with Network Load Balancing.
As multiple desktops had enabled the load balancing feature, the MAC 02:01:00:00:00:00 got flooded throughout the network and gave rise to a STP loop.
To solve this, we found the ports with machines having the ânetwork load balancingâ feature enabled and manually shut those ports.
-Sai.
03-18-2008 03:48 AM
hi sai,
try to figure out any wireless access
provided which may lead to host flapping
an possibility
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