[pve-devel] MAC address generation

Thomas Lamprecht t.lamprecht at proxmox.com
Fri Jul 8 13:14:30 CEST 2016

On 07/08/2016 12:33 PM, Waschbüsch IT-Services GmbH wrote:
>> Am 07.07.2016 um 17:26 schrieb Andreas Steinel <a.steinel at gmail.com>:
>> Hi,
>> I currently only have one big 3.4 install (>150 VMs), on which I compared
>> the generated MACs and found out that they are completely random. Are there
>> plans or probably is there already an implementation to generate only from
>> a specific region? I did not found any changes in the roadmap.
>> In KVM/Qemu there is standard to use a prefix of 52:54:00, which was
>> present in Proxmox some years ago.
> While we are at it: are generated MAC addresses ensured to be unique across a cluster?

Not directly, although the chance of such a collisions is about:

0.000 000 000 000 355 271 % or 1 in 10 ^ 14.5

so if a problem arise I'd call it your lucky day, still you have a point.

It would not be that much of a problem to check it between the VMs/CTs, 
I guess, but for other devices in the network... (prefix could help here)

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