What Is a MAC Address?
A MAC address is the 48-bit hardware ID of a network card. How the OUI gives away the vendor, how to find yours on any OS, randomization, and MAC vs IP.
What Is a MAC Address?
A MAC address (Media Access Control address) is the hardware identifier of a network interface card (NIC). IP addresses work at the network layer (OSI Layer 3) and move data across the internet; MAC addresses work one level down, at the data link layer (Layer 2), and move data across the local segment you are on. Anything with a network port has one: laptops, phones, smart TVs, printers, IoT gadgets. A device with both Wi-Fi and Ethernet has one MAC per interface.
MAC Address Format
A MAC is 48 bits (6 bytes), written as six pairs of hex digits with colons or hyphens: 00:1A:2B:3C:4D:5E or 00-1A-2B-3C-4D-5E. The two halves mean different things:
| Portion | Bits | Bytes | Purpose | Example |
|---|---|---|---|---|
| OUI (Organizationally Unique Identifier) | First 24 bits | Bytes 1 to 3 | Identifies the manufacturer/vendor | 00:1A:2B |
| NIC Specific | Last 24 bits | Bytes 4 to 6 | Unique identifier assigned by manufacturer | 3C:4D:5E |
Two bits in the first byte carry extra meaning:
- Bit 0 (least significant): 0 = unicast, 1 = multicast
- Bit 1: 0 = globally unique (set by the manufacturer), 1 = locally administered (overridden by software)
OUI: Identifying the Vendor
The IEEE assigns the OUI, the first three bytes, to hardware makers. Look it up and you know who built the interface:
| OUI Prefix | Vendor |
|---|---|
00:50:56 | VMware |
00:0C:29 | VMware (another range) |
DC:A6:32 | Raspberry Pi Foundation |
F8:FF:C2 | Apple |
3C:5A:B4 | |
B4:2E:99 | Samsung |
00:15:5D | Microsoft (Hyper-V) |
Our MAC Address Lookup finds the vendor for any MAC address.
How to Find Your MAC Address
| Operating System | Command | Look For |
|---|---|---|
| Windows | ipconfig /all | "Physical Address" under your network adapter |
| macOS | ifconfig en0 | "ether" field |
| Linux | ip link show | "link/ether" field |
| Android | Settings → About Phone → Status → Wi-Fi MAC address | MAC address field |
| iOS | Settings → General → About → Wi-Fi Address | Wi-Fi Address field |
On Windows, getmac /v prints a tidy list of every adapter and its MAC.
MAC Address Spoofing and Randomization
Spoofing means telling the OS to send a different MAC in its frames; the hardware address stays, only what goes on the wire changes. People do it for privacy (no tracking from one Wi-Fi network to the next), to get past MAC filtering on whitelisted networks, or as admins testing MAC-based access controls. Modern systems randomize for you:
- iOS 14+ and Android 10+ use a random MAC for each Wi-Fi network by default.
- Windows 10/11 has an optional "Random hardware addresses" setting for Wi-Fi.
- macOS Sequoia+ supports private Wi-Fi addresses.
MAC Address vs IP Address
| Feature | MAC Address | IP Address |
|---|---|---|
| OSI Layer | Layer 2 (Data Link) | Layer 3 (Network) |
| Scope | Local network only | Local and internet |
| Assignment | Hardware manufacturer (or randomized) | DHCP server or manual config |
| Persistence | Typically permanent (burned into NIC) | Can change with network/DHCP |
| Format | 48-bit hexadecimal (00:1A:2B:3C:4D:5E) | 32-bit decimal (IPv4) or 128-bit hex (IPv6) |
| Routable | No, only within the local segment | Yes, routed across the internet |
One thing that surprises people: as a packet crosses the internet the IP addresses stay the same the whole way, but the MAC addresses change at every hop. Each router rewrites them to its own MAC and the next hop's.
Try it on a real address. Free, no account needed.