Random MAC address rules incorrect (conflicts with reserved OUIs)

[SuffieldAcademy]

Inspecting the random MAC address assigned to Adapter 1 on one of my virtual machines, it looks wrong to me. Hitting the "generate" button produces MAC addresses with the prefix 08-00-27.

According to ​http://standards.ieee.org/develop/regauth/oui/oui.txt, that prefix is owned by another company (Cadmus).

Additionally, the mouseover help text mentions that one must pick any MAC where "the second character is an even digit". That is incorrect as demonstrated above (08-XX-XX has many registered owners).

There is reference on the mail lists to this problem being known: https://www.virtualbox.org/pipermail/vbox-dev/2011-August/010036.html

However, that's two years old and no progress on getting an official OUI.

In the meantime, I suggest selecting MAC addresses from the "Locally-Assigned" prefix. The IEEE states that any MAC with the 6th bit in the most significant octet set to 1 is "local" instead of "globally unique". Excluding multicast MAC addresses (bit 7 set to 1), that yields prefixes where the second digit is one of: 2, 6, A, or E. Put another way:

X2:XX:XX:XX:XX:XX, X6:XX:XX:XX:XX:XX, XA:XX:XX:XX:XX:XX, XE:XX:XX:XX:XX:XX

Are all valid locally-assigned MACs, where "X" is any hex digit. There are plenty of "fake OUIs" you can generate in this range without needing to get a legitimate OUI and without conflicting with known registered OUIs.

As a minimal modification, just changing the "08" to "06" in the prefix you use and instructing users to select any MAC that starts with "06" would be OK. It's technically overly restrictive, but most users wouldn't care and it would give the same experience as the current system without violating the IEEE assignments.

[Akhilesh]

I can see following are OUI in IEEE OUI database:- Are these valid globally:--

02-07-01 "RACAL-DATACOM"

02-1C-7C "PERQ SYSTEMS CORPORATION"

02-60-86 "LOGIC REPLACEMENT TECH. LTD."

02-60-8C "3COM"

02-70-01 "RACAL-DATACOM"

02-70-B0 "M/A-COM INC. COMPANIES"

02-70-B3 "DATA RECALL LTD."

02-9D-8E "CARDIAC RECORDERS, INC."

02-AA-3C "OLIVETTI TELECOMM SPA (OLTECO)"

02-BB-01 "OCTOTHORPE CORP."

02-C0-8C "3COM"

02-CF-1C "Communication Machinery Corporation"

02-E6-D3 "NIXDORF COMPUTER CORP."

AA-00-00 "DIGITAL EQUIPMENT CORPORATION"

AA-00-01 "DIGITAL EQUIPMENT CORPORATION"

AA-00-02 "DIGITAL EQUIPMENT CORPORATION"

AA-00-03 "DIGITAL EQUIPMENT CORPORATION"

AA-00-04 "DIGITAL EQUIPMENT CORPORATION"

[Klaus Espenlaub]

All OUI registrations are global. The idea is that with a unique OUI and (usually) 24 bits uniquely assigned by the OUI owner every MAC address is globally unique. Non-unique MAC addresses in a LAN would cause chaos.

I never understood the issue raised above. Yes, it's possible that there are devices out there which are sold by the OUI owner, but did anyone criticizing this re-use ever check if the owner still exists and when they might have last sold any device?

And I also don't understand what's wrong about the mouseover help text - the intention of it is to steer people away from multicast or broadcast addresses, that's all. Anything else is valid, and it is up the user to know if he'd run into trouble (due to non-unique addresses) or not. There can be valid reasons for using a specific MAC address, and the GUI would make a mistake if it would flag that as invalid.