What this means
The IEEE assigned the MA-L block C4491B 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 C4:49:1B, it is Apple, Inc. hardware.
Frequently Asked Questions
Who owns MAC prefix C4491B?
C4491B 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 C4491B?
Any network device with a MAC address starting C4:49:1B was manufactured by or for Apple, Inc..