What Is a MAC Address?
What Is a MAC Address?
A MAC address (Media Access Control address) is a unique hardware identifier assigned to every network interface card (NIC) in a device. While IP addresses identify devices at the network layer (Layer 3), MAC addresses operate at the data link layer (Layer 2) of the OSI model and are used for communication within a local network segment.
Every device with a network connection - laptops, phones, smart TVs, printers, IoT devices - has at least one MAC address. Devices with both Wi-Fi and Ethernet have separate MAC addresses for each interface.
MAC Address Format
A MAC address is a 48-bit (6-byte) identifier, typically written as six pairs of hexadecimal digits separated by colons or hyphens:
00:1A:2B:3C:4D:5E or 00-1A-2B-3C-4D-5E
The 48 bits are divided into two halves:
| Portion | Bits | Bytes | Purpose | Example |
|---|---|---|---|---|
| OUI (Organizationally Unique Identifier) | First 24 bits | Bytes 1–3 | Identifies the manufacturer/vendor | 00:1A:2B |
| NIC Specific | Last 24 bits | Bytes 4–6 | Unique identifier assigned by manufacturer | 3C:4D:5E |
Special bits in the first byte carry additional meaning:
- Bit 0 (least significant): 0 = unicast, 1 = multicast
- Bit 1: 0 = globally unique (manufacturer-assigned), 1 = locally administered (overridden by software)
OUI: Identifying the Vendor
The OUI (Organizationally Unique Identifier) - the first three bytes of the MAC address - is assigned by the IEEE to hardware manufacturers. By looking up the OUI, you can identify which company made the network 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) |
Use our MAC Address Lookup tool to identify 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, you can also open Command Prompt and run getmac /v for a clean list of all adapters and their MAC addresses.
MAC Address Spoofing and Randomization
MAC spoofing is the practice of changing your device's MAC address to a different value. This is done in software - the hardware address remains the same, but the OS sends a different value in network frames.
Reasons for spoofing:
- Privacy: Prevents tracking across different Wi-Fi networks.
- Bypass MAC filtering: Some networks restrict access based on MAC address whitelists.
- Testing: Network administrators test MAC-based access controls.
Modern operating systems now include MAC address randomization for privacy:
- iOS 14+, Android 10+: Use a random MAC for each Wi-Fi network by default.
- Windows 10/11: 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 |