Mac flap

[kamleshkatariya1994]

If 2 MAC learners are running on a single port then the issue of flapping arises.

[MHM Cisco World]

No 

Flapping is when one mac learn from two different port.

2 mac per one port is OK the SW is not log that there is flapping 

MHM

[kamleshkatariya1994]

But mac is same 

[MHM Cisco World]

Sorry what is same' you mention two mac learn in one port ?

Can you elaborate 

MHM

[kamleshkatariya1994]

Two same mac lurn on single port in cisco switche

[MHM Cisco World]

Ok' this normal if this mac is for ipphone and it learn in data vlan and voice vlan.

Abd here the SW no show flapping log for this case.

MHM

[kamleshkatariya1994]

A sub-interface is created in the firewall and installed on its link port. Has been done. Two same MACs are visible on this port. So what could be the reason for flapping?

1          18:b1:69:f4:69:8c   gi1  dynamic
11       18:b1:69:f4:69:8c   gi1  dynamic

[MHM Cisco World · Accepted solution]

Subinterface is config in FW the SW port must config with trunk and you must check native vlan' it must match between FW and SW trunk port 

MHM