DaveSchroeder01
Contributor
Contributor

Prefix of MAC address in VMware ESXi

Dear all, 

I am trying to figure out why the prefix of my adapters are different when looking up in VMware and comparing it to the ones listed in CIMC (Cisco Integrated Management Controller) management layer. 

For instance, one of the ethernet card adapters in the CIMC layer is listed as:

A0:3D:6C:0B:E6:80

whereas in the VMware management layer under "Network Adapters" after checking which one is connected I get,

vmnic1: A0:3D:6C:0B:E6:8c

Is it related to an automatic MAC address generation on the ESXI host in order to prevent MAC address conflicts or what's the reason behind this prefix change? I am also a bit confused which one is now the right one to share with the admin in our department in order to get the right MAC address registered?

I am grateful for any help!

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3 Replies
a_p_
Leadership
Leadership

ESXi doesn't change hardware MAC addresses.
Please double-ceck the CIMC network configuration. Maybe it has multiple addresses, or has some spechial profile configuration applied!?

André

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DaveSchroeder01
Contributor
Contributor

I just recently installed VMware ESXI and didn't apply any profile configuration to the network configuration. 

However, what I observe is that I have two mac addresses listed for one ethernet card adapter.

In the CIMC layer:

A0:3D:6C:0B:E6:80

A0:3D:6C:0B:E6:81

and in the VMware management layer:

vmnic1: A0:3D:6C:0B:E6:8c

vmnic2: A0:3D:6C:0B:E6:8d

Does this mean that there are multiple addresses? 

 

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a_p_
Leadership
Leadership

That's indeed possible. From what I know, Cisco has network adapters which can present themselves as multiple logical NICs with individual MAC addresses.

André

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