What this means
The IEEE assigned the MA-L block AC91A1 to Dell 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 AC:91:A1, it is Dell Inc. hardware.
Frequently Asked Questions
Who owns MAC prefix AC91A1?
AC91A1 is registered to Dell 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. Dell Inc.'s block covers 16,777,216 addresses.
What devices use AC91A1?
Any network device with a MAC address starting AC:91:A1 was manufactured by or for Dell Inc..