MAC address FA:7A:CB details

Assigned Prefix
FA:7A:CB

24-bit Prefix (CID)

Block Base Allocation
FA:7A:CB:00:00:00

Hardware Interface 0x000000 (Min)

Block Top Boundary
FA:7A:CB:FF:FF:FF

Hardware Interface 0xFFFFFF (Max)

Network Addressing & Host Scope

CID

This assignment represents an IEEE CID (Company ID) allocation in the locally administered space, spanning a 48-bit range of 16,777,216 addresses (not intended for globally unique hardware MAC assignment).

START: FA:7A:CB:00:00:00 16,777,216 Total Addresses END: FA:7A:CB:FF:FF:FF
Lower Bound (Base Host 0) Upper Bound (Top Boundary)
IEEE Registry Tier CID Locally Administered (LAA)
48-Bit Range Size 16,777,216 Exact binary space: 224 addresses
IEEE CID & Randomization Overlap: A Company ID (CID) is officially assigned by the IEEE as a 24-bit organization identifier in the locally administered space (U/L = 1). CID values have A as the second hexadecimal digit, with I/G = 0. Randomized Wi-Fi addresses can coincidentally match the prefix FA:7A:CB. A matching prefix does not establish that a device belongs to the CID registrant or that its address was randomized.

A CID can be extended into Extended Local Identifiers (ELIs); their uniqueness must be managed within the local network. A CID does not allocate globally unique EUI-48 or EUI-64 addresses.

IEEE Company ID guidance
Derived IPv6 Link-Local SLAAC Base RFC 4291 EUI-64
fe80::f87a:cbff:fe00:0000

Base address derived from the allocation start, not a network prefix or a verified configured address. The link-local subnet is fe80::/64.

RFC 4291 (Modified EUI-64): This example derives an interface identifier from a 48-bit MAC address by inserting ff:fe and inverting the universal/local bit. An interface can use a different IPv6 identifier.

Octet & Bit Architecture

24-Bit Architecture
Allocation Spread 24-BIT PREFIX (50%) + 24-BIT HOST (50%)
24-Bit Prefix
24-Bit Host
Bit 0 [FA:7A:CB]
Bit 24
Bit 47 [Host Top]

OUI / Prefix OUI means Organizationally Unique Identifier. MA-L uses a 24-bit prefix; MA-M and MA-S use 28-bit and 36-bit prefixes.

Host bits The remaining bits define the address space within the allocation.

Binary Octet Breakdown (Prefix)

Colored bits in Octet 0 (the first byte) match the I/G and U/L cards below. Octet indices start at zero.

Octet 0 FA 1111 10 1 0
Octet 1 7A 0111 1010
Octet 2 CB 1100 1011
First octet, bit 1 (U/L) b1 = 1
Locally Administered (LAA)

CID uses local address space; the prefix alone does not identify device origin.

First octet, bit 0 (I/G) b0 = 0
Unicast Transmission

Individual address destination (point-to-point transmission).

Wireshark Dissector Intel
Display Filter: eth.addr[0:3] == fa:7a:cb
No custom Wireshark manufacturer alias overrides registered for this prefix.

REST API v2

200 OK
CLI curl -s https://api.maclookup.app/v2/macs/fa7acb -H 'Accept: application/json'
{
  "success": true,
  "found": true,
  "macPrefix": "FA7ACB",
  "company": "Ultra Ethernet Consortium",
  "address": "c/o The Linux Foundation, 548 Market St. PMB 57274, San Francisco CA 94104-5401, US",
  "country": "US",
  "blockStart": "FA7ACB000000",
  "blockEnd": "FA7ACBFFFFFF",
  "blockSize": 16777215,
  "blockType": "CID",
  "updated": "2025-03-14",
  "isRand": true,
  "isPrivate": false
}