[c-nsp] Problem VLAN Flapping between trunk port

[Peter Rathlev]

On Tue, 2011-05-31 at 22:11 -0700, Md. Jahangir Hossain wrote:
...
> *Mar  1 12:43:54: %SW_MATM-4-MACFLAP_NOTIF: Host 0018.d17b.96d7 in
> vlan 104 is flapping between port Gi1/0/28 and port Gi1/0/27

What's behind these ports?

The switch is complaining that the MAC address keeps moving. It could be
a loop, but most often (in my experience) it's "misconfigured" hosts,
e.g. a host with dual NICs that's using some kind of load-sharing
between ports. I also seem to remember seeing it when IP phones roam
between wireless access points.

>From the port configuration it must be something you trust not to bridge
itself. A VMware server maybe?

-- 
Peter