Building B, Inc

MA-L

MA-L: a full /24 OUI block, IEEE's largest, covering 16,777,216 addresses.

Prefix00:21:33:00:00:00 /24

Vendor address1000 NW 65th Street, Suite 300 Ft. Lauderdale FL US 33309

RegisteredApr 14, 2008

Block range00:21:33:00:00:00– 00:21:33: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

00:21:33:00:00:00 00:21:33:7F:FF:FF 00:21:33:FF:FF:FF

Where this block sits

Previous 00:21:32:00:00:00 /24 Masterclock, Inc. Next 00:21:34:00:00:00 /24 Brandywine Communications

The nearest registered blocks of the same size on either side of this one in IEEE's address space.

Building B, Inc holds 1 registered blocks in the IEEE registry, ranking #7,522 of 33,427 organizations by block count.