IP And MAC Address Issue

[SamsonOjo]

I am having issue with one of my desktops connected to my switch interface flipping between two MAC addresses (see the attached picture below for log). When I disconnect the desktop the IP and the MAC issues will not show in the log. I reimaged the desktop and plugged it back in but the issue reoccurred. Please can anyone assist with a solution?

[MHM Cisco World]

It issue from PC itself not SW nor dhcp.

You can use port secuirty one port with restricted' but I prefer solve issue from PC OS not from add command in SW

MHM

[balaji.bandi]

Looking at the output the device using Intel Etherent adaptor, check any Hyper-V running on the PC.

[pieterh]

i agree, most likely one of the adresses is the virtual switches MAC address

this can also occur if this computer has a management processor (iDRAC ?) with its network interface in the BIOS configured as shared with the normal NIC 
-> can you be more specific about the model ?

[Jens Albrecht]

Hello @SamsonOjo,

based on the MAC address you are using an Intel NIC and especially those with multiple ports or advanced features (e.g., X710, X550, E810), can present more than one MAC address per physical adapter. Also features like SR-IOV or certain BIOS/firmware settings can cause a NIC to present multiple MAC addresses or duplicate MACs across virtual adapters.

There are a few things you could check:

• Update the drivers and the firmware of the Intel NIC to make sure that you have the latest versions for your adapter.
• Check the adapter settings under Network Adapter Properties → Advanced → "Locally Administered Address" and ensure no custom MAC is set.
• Disable any unused virtual adapters.
• Review the BIOS/UEFI settings, i.e. check for SR-IOV or virtualization settings and test toggling them.
• Disable energy-efficient Ethernet or power-saving features.

HTH!

[Leo Laohoo]

First, find out where the two MAC addresses are connected in the switch. 

Do a continuous ping to the offending IP address and then disable the port of one of the MAC address.  Is the ping still active?  

[SamsonOjo]

I removed the desktop, and I no longer see the IP and double MAC addresses. I will leave it that way. Thank you all for all your responses.