What this means
The IEEE assigned the MA-L block 5821E9 to TWPI. 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 58:21:E9, it is TWPI hardware.
Frequently Asked Questions
Who owns MAC prefix 5821E9?
5821E9 is registered to TWPI 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. TWPI's block covers 16,777,216 addresses.
What devices use 5821E9?
Any network device with a MAC address starting 58:21:E9 was manufactured by or for TWPI.