MAC address B4:EF:30 details

Assigned Prefix
B4:EF:30

24-bit Prefix (MA-L)

Block Base Allocation
B4:EF:30:00:00:00

Hardware Interface 0x000000 (Min)

Block Top Boundary
B4:EF:30:FF:FF:FF

Hardware Interface 0xFFFFFF (Max)

Network Addressing & Host Scope

MA-L

This assignment represents an IEEE MA-L allocation, granting a dedicated boundary of 16,777,216 unique host MAC addresses.

START: B4:EF:30:00:00:00 16,777,216 Total Addresses END: B4:EF:30:FF:FF:FF
Lower Bound (Base Host 0) Upper Bound (Top Boundary)
IEEE Registry Tier MA-L Universally Administered (UAA)
Total Host Capacity 16,777,216 Exact binary space: 224 addresses
Derived IPv6 Link-Local SLAAC Base RFC 4291 EUI-64
fe80::b6ef:30ff: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 [B4:EF:30]
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 B4 1011 01 0 0
Octet 1 EF 1110 1111
Octet 2 30 0011 0000
First octet, bit 1 (U/L) b1 = 0
Universally Administered (UAA)

Globally unique IEEE governed address.

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] == b4:ef:30
No custom Wireshark manufacturer alias overrides registered for this prefix.

REST API v2

200 OK
CLI curl -s https://api.maclookup.app/v2/macs/b4ef30 -H 'Accept: application/json'
{
  "success": true,
  "found": true,
  "macPrefix": "B4EF30",
  "company": "Shanghai SYH Technology CO.,LTD",
  "address": "Building 4, No. 686 Nanfeng Road, Fengcheng Town, Fengxian District, Shanghai  201400, CN",
  "country": "CN",
  "blockStart": "B4EF30000000",
  "blockEnd": "B4EF30FFFFFF",
  "blockSize": 16777215,
  "blockType": "MA-L",
  "updated": "2025-04-28",
  "isRand": false,
  "isPrivate": false
}