ā01-31-2012 12:03 AM - edited ā03-07-2019 04:39 AM
Hello everybody.
Got this log entry, repeated many times:
%SW_MATM-4-MACFLAP_NOTIF: Host 2c76.8aae.410e in vlan 1 is flapping between port Gi1/0/11 and port Gi2/0/12
It is happening on a stacked switch...
What's this and how to solve it? For me, it looks like a device being connected or trying to get connected on two different switch ports (loop?!)...
Kind regards and thanks.
F.
ā01-31-2012 12:07 AM
Hi Flavio,
SO you get some packet looped from device with MAC 2c76.8aae.410e. You can see packet is coming both from Gi1/0/11 and Gi2/0/12. You need to trace that mac down to the end device and see why this packet taking both pathes to your switch.
Causes can be:
- link flapping issue triggering packet to take another part
- that in turn can cause STP loops
etc.
Nik
ā01-31-2012 01:03 AM
Hi Flavio,
That error implies the switch is seeing the same MAC in serveral ports.Do you have the same server connected to different ports without configuring etherchannel on it?
You may using blade server for this one the flapping is between the blade server.
You should group those ports in a port-channel but, in your case, is impossible because one of the ports is a trunk. I recommend you change one of the ports of that Blade to another switch where you can configure a etherchannel with them (stack switches, same switch).
Please find the below some of the errors messages
18w2d: %SW_MATM-4-MACFLAP_NOTIF: Host 0201.0000.0000 in vlan 7 is flapping between port Gi0/2 and port Gi0/11
18w2d: %SW_MATM-4-MACFLAP_NOTIF: Host 0201.0000.0000 in vlan 7 is flapping between port Gi0/2 and port Gi0/11
18w2d: %SW_MATM-4-MACFLAP_NOTIF: Host 0201.0000.0000 in vlan 1 is flapping between port Gi0/16 and port Gi0/17
18w2d: %SW_MATM-4-MACFLAP_NOTIF: Host 0201.0000.0000 in vlan 7 is flapping between port Gi0/11 and port Gi0/10
18w2d: %SW_MATM-4-MACFLAP_NOTIF: Host 0201.0000.0000 in vlan 7 is flapping between port Gi0/2 and port Gi0/11
says that the server is using the links in active/active configuration.
To avoid to confuse the lan switch you need to use bundles of ports.
you can create two etherchannel bundles one made of 5 ports for vlan 1 and one made of 5 ports for vlan 7.
something like:
int gi4/x
switchport
switchport mode access
switchport access vlan 7
channel-group 7 active
on all 5 ports in vlan 7
int gi4/x
switchport
switchport mode access
switchport access vlan 1
channel-group 1 active
you can check if these etherchannel groups are free with
sh etherchannel summary
on blade switch
int gi0/y
switchport
switchport mode access
switchport access vlan 7
channel-group 7 active
on all 5 ports in vlan 7
int gi0/y
switchport
switchport mode access
switchport access vlan 1
channel-group 1 active
Note: you need to do the same on the blade switch in this way you build two bundles and all the MAC address flapping confusion will end
Please rate all the helpfull posts.
Regards,
Naidu.
ā08-18-2012 12:14 AM
I am assuming you are using Windows Server 2003, & to get rid of this pesky MAC address that keeps appearing across your MAC tables you need to go to Network adapter settings -> highlight your adapter --> right click --> Properties--> and Untick 'Network Load Balancing'.
Thanks
Subramanian Iyer
CISCO ASA QA
ā05-18-2021 01:54 AM
This method is usefulļ¼the problem has been solved, Thank you !
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