What this means
The IEEE assigned the MA-L block 40331A to Apple, Inc.. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 40:33:1A, it is Apple, Inc. hardware.
Frequently Asked Questions
Who owns MAC prefix 40331A?
40331A is registered to Apple, Inc. in the IEEE MA-L registry.
What does the MA-L registry type mean?
An MA-L assignment, the IEEE's original OUI format, gives the vendor the first three octets and 16,777,216 device addresses under them. Apple, Inc.'s block covers 16,777,216 addresses.
What devices use 40331A?
Any network device with a MAC address starting 40:33:1A was manufactured by or for Apple, Inc..