MA-L: a full /24 OUI block, IEEE's largest, covering 16,777,216 addresses.
Prefix00:21:3C:00:00:00 /24
Vendor address150 Executive Park Blvd San Francisco CA US 94134
Country🇺🇸 United States
RegisteredJun 18, 2008
Block range00:21:3C:00:00:00– 00:21:3C:FF:FF:FF
Address capacity16,777,216
AdministrationUniversally administered: its prefix comes from a block registered through the IEEE Registration Authority
TransmissionUnicast: addressed to a single device
SourceIEEE Registration Authority
Address capacity is the size of this registered block, not a count of devices actually manufactured or online. Registration identifies the organization holding the block, not a specific device model or unit.
Curious how a prefix like this turns into a full address? See how MAC addresses are structured →
Example addresses in this block
Where this block sits
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00:21:3B:00:00:00 /24
Berkshire Products, Inc
Next
00:21:3D:00:00:00 /24
Cermetek Microelectronics, Inc.
The nearest registered blocks of the same size on either side of this one in IEEE's address space.
AliphCom holds 1 registered blocks in the IEEE registry, ranking #4,714 of 33,427 organizations by block count.