Two MAC Addresses in "show mac address-table" for a single host in CISCO 6509E Layer-3 Switch.

[nkbeet]

Hi,

May I know, why 2 different mac addresses of a server are being shown of CISCO 6500E Layer-3 Switch ? One server having one nework adapter (MAC ID : xxxx.xxxx.xx0c) is connected to an interface of Cisco Layer-3 6509E Switch. But on running the command "show mac address-table", the output shows two mac addresses, one of the server (xxxx.xxxx.xx0c) an another one MAC ID as xxxx.xxxx.xx0e. Even after applying the command "switchport port-security mac-address xxxx.xxxx.xx0c", the output remains same.

With regards,

[balaji.bandi]

clear ip arp and check, what is this device ? server running any virtual host ?

show ip arp - see related mac address has any IP addres

[nkbeet]

Thanks for prompt reply. 

There is no virtual host. There is only one nework adapter on this Server. The mac address is 2 up than actual mac address, i.e., the actual mac is xxxx.xxxx.xxx0c, and the unknown mac is xxxx.xxxx.xxx0e (i.e., c+2=e).

[balaji.bandi]

Thank you for the confirmation there is no Virtiual Host inside that device.

Can you track with MAC address associated with IP address - see who is the manifacturer  ?

also test, if you see 2 MAC address with 2 IP address, is the 2 IP address ping ?

as suggested you can look with Vendor - may be some driver upgrade may required on end device to stop producing different MAC address.

[Georg Pauwen]

Hello,

can you post the MAC addresses here, or use the tool below to find out what vendor these MAC addresses belong to ? That might render a clue as to where they come from...

https://macvendors.com/