Understanding MAC Addresses | Generated by AI
Yes, you’re basically correct! Here’s a clear and complete explanation of what a MAC address (always written in uppercase as MAC) is:
What is a MAC address?
- MAC = Media Access Control address
- It’s a unique 48-bit hardware identifier (usually written as 6 groups of 2 hexadecimal digits, e.g.,
00:1A:2B:3C:4D:5Eor00-1A-2B-3C-4D-5E) - It is burned into the hardware of a network interface (Ethernet card, Wi-Fi card, Bluetooth chip, etc.) by the manufacturer at the factory.
- It operates at Layer 2 (Data Link layer) of the OSI model — used for local network communication (within the same LAN/broadcast domain).
Key characteristics you got right:
- Hardware-bound: Yes, it’s tied to the physical network interface controller (NIC).
- Assigned at factory: The first half (first 3 bytes = 24 bits) is the OUI (Organizationally Unique Identifier), assigned by the IEEE to the manufacturer (e.g., Apple, Intel, Realtek, etc.).
- Globally managed: The IEEE maintains a public registry so (in theory) no two devices in the world should have the same MAC if properly manufactured.
- Not supposed to change: The real hardware MAC is permanent.
But… there are important exceptions (software can override it):
Even though the real burned-in MAC is fixed, most operating systems allow you to temporarily change/spoof the MAC address in software:
- Windows: Through device manager or tools like TMAC
- Linux/macOS:
ifconfig,ip link, ormacchanger - Purpose: Privacy (e.g., on public Wi-Fi), testing, bypassing MAC-based restrictions, etc.
When you spoof it:
- The device tells the network: “Hi, my MAC is now XX:XX:XX:XX:XX:XX”
- This change is temporary — disappears after reboot (unless scripted)
- The real burned-in MAC remains unchanged in the hardware
Summary table:
| Property | True for real MAC? | Can be changed in software? |
|---|---|---|
| Assigned by manufacturer | Yes | No |
| Globally unique (ideally) | Yes | Only if not spoofed |
| Burned into NIC hardware | Yes | No |
| Used for local LAN delivery | Yes | Yes (even if spoofed) |
| Can be temporarily changed | — | Yes (spoofing) |
| Survives OS reinstall | Yes | No (spoofed one is lost) |
Quick way to see your current MAC:
- Windows:
getmacoripconfig /all - Linux/macOS:
ifconfigorip link
So yes — you’re 95% correct: the real MAC address is permanent, hardware-bound, and globally administered. The only reason people say “MAC can be changed” is because of software spoofing, which doesn’t touch the actual hardware value.