IEEE 802 Standard · OUI Lookup · Layer 2 Data Link

MAC Address Lookup & OUI Converter

Identify device manufacturers from IEEE OUI prefixes, detect private randomized MAC addresses, and reformat between Cisco dot, hyphen, and colon styles.

Try Example MAC:

MAC Address or OUI Prefix (Any Format Supported)

Hardware Manufacturer & OUI Info

Vendor / Company

Raspberry Pi Foundation

OUI Prefix (24 bits)

B8:27:EB

NIC Specific (24 bits)

48:9A:F1

Unicast (Physical Device)Universally Administered (IEEE OUI)

Colon Delimited

B8:27:EB:48:9A:F1

Hyphen Delimited

B8-27-EB-48-9A-F1

Cisco Dot Notation

b827.eb48.9af1

Bare Hexadecimal

B827EB489AF1

48-Bit Binary Representation

10111000:00100111:11101011:01001000:10011010:11110001

Anatomy of an IEEE 802 MAC Address

1. OUI (First 24 Bits)

The first 3 octets (e.g. B8:27:EB) represent the Organizationally Unique Identifier assigned to hardware manufacturers by the IEEE Registration Authority.

2. NIC Specific (Last 24 Bits)

The remaining 3 octets are serialized by the vendor to create a globally unique physical network card identifier on the Ethernet / Wi-Fi Layer 2 data link segment.

3. Private MAC Randomization

Modern mobile operating systems (iOS "Private Wi-Fi Address" and Android MAC randomization) flip the U/L bit (bit 1 of octet 1). If the second hexadecimal digit is 2, 6, A, or E, the address is ephemeral and generated to prevent retail tracking.

First Octet Special Bit Flags (IEEE 802.3)

I/G Bit (Bit 0 - Individual / Group):

0 indicates a Unicast transmission sent to a single recipient device. 1 indicates a Multicast or Broadcast packet destined for all devices on the switch domain.

U/L Bit (Bit 1 - Universal / Local):

0 indicates a manufacturer-assigned globally unique address. 1 indicates a locally administered address assigned by a network admin or software privacy randomizer.