macadress

Alcad SL

MA-L
MA-L: a full /24 OUI block, IEEE's largest, covering 16,777,216 addresses.
Prefix00:1D:21:00:00:00 /24
Vendor addressPol. Ind. Arreche-Ugalde, 1 Irún Guipúzcoa ES E-20305
Country🇪🇸  Spain
RegisteredAug 18, 2007
Block range00:1D:21:00:00:00– 00:1D:21: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 →

Ownership timeline

  1. Aug 18, 2007 – Jun 23, 2009 Alcad S.A. name changed
  2. Jun 23, 2009 – present Alcad SL

Example addresses in this block

00:1D:21:00:00:00 00:1D:21:7F:FF:FF 00:1D:21:FF:FF:FF

Where this block sits

Previous 00:1D:20:00:00:00 /24 Comtrend Corporation Next 00:1D:22:00:00:00 /24 Foss Analytical A/S

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

Alcad SL holds 1 registered blocks in the IEEE registry, ranking #4,624 of 33,421 organizations by block count.