VMware Cloud Community
ablej
Hot Shot
Hot Shot

When are new MAC addresses generated

Does anyone have a list of situations that generate a new MAC address. Such as a cold migration, UUID change, Clone, etc....

David Strebel www.david-strebel.com If you find this information useful, please award points for "correct" or "helpful"
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Ajay_Nabh
Enthusiast
Enthusiast

MAC address will only generate when you will add or remove NIC to VM or you Manually change MAC address, I don't see why MAC address would change as it is only attached to NIC not to VM!!

However it will good to hear from experts

Cheers

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ablej
Hot Shot
Hot Shot

I know at least it will change when you generate a new UUID and I know with previous versions a cold clone would also regenerate a MAC. I think clones also regenerate MAC, so would like to see if there is a definitive list for each version of ESX.

-David

David Strebel www.david-strebel.com If you find this information useful, please award points for "correct" or "helpful"
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danm66
Expert
Expert

yes, anytime a VM is booted, the host (and VC if it's connected to one) checks other running VM's to see if the MAC is already being used and generates a new MAC for the booting VM.

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weinstein5
Immortal
Immortal

As others have indicated a MAC address is generated every time a VM is powered on - the MAC address is generated using the UUID of the ESX and the directory location of the V<s configuration file - you can also set the MAC address in the configuration file and a MAC will never get generated for this VM -

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful
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sarank
Enthusiast
Enthusiast

Hi,

Major two things will involve to generate or change the MAC address

1.When cloning the machine(if MAC conflict)

2.Converting V2V or P2V

We can generate the new MAC and avoid the conflicts.

I hope it will help you.

IF you are satisfied means reply as "correct" or "Helpful"

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AWo
Immortal
Immortal

Read KB 219, it contains a lot of information regarding the MAC address handling in ESX.


AWo

VCP 3 & 4

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