3 mac addresses on one interface+

[girish_p1]

Hi, Can anyone help me to understand that I have a switch port connected with an IP Phone and a PC but it is showing 3 mac addresses on this port. Phone is in voice vlan 30 and port is in vlan 10 but I see two mac addresses on vlan 10 and one on vlan 30 on this interface when i run sh mac-add-table inter <current>. 

Can anyone explain that ? Thanks in advance.

[omz]

Hi, 

Lookup the mac address to find out the vendor. That might help.

https://macvendors.com/

Any other NIC on the PC? Wireless or Virtual?

[sbhadrav@cisco.com]

Provides the output for ports G1/0/10 thru 19:

sh mac address-table | include Gi1/0/([1][0-9])

Provides the outputs for G1/0/20 thru 39:

sh mac address-table | include Gi1/0/([2-3][0-9])

[thilinar8]

can you share the switch port config?

is phone MAC address shown in both VLANs?

[Martin Carr]

Are you sure no one has connected a switch to the interface?

Martin