You’re correct … it could put a big dent in laptop burglaries if MAC addresses were truly traceable. It would at least increase the odds of stolen equipment being recovered.
But they’re not traceable… at least not in any way that could help.
Let’s look at why.
MAC addresses are unique – sort of
A MAC1 address, or “Media Access Control” address, is a unique 48-bit number2 assigned to every network interface. If your computer has multiple network interfaces – say both a wired ethernet port and a wireless network adapter – each interface will have its own MAC address.
In theory, it’s unique. In theory, every network card or network interface should have its own unique MAC address that is different from every other network card on the planet.
There are two problems:
- Occasionally, manufacturers don’t ensure they’re unique, so multiple network interfaces can in fact have the same MAC address.
- In many network interfaces, the MAC address can be set in software – meaning whatever the original MAC address, it can be overridden and changed.
So the uniqueness on which we might want to rely is not completely reliable.
But that isn’t really the biggest problem.
MAC addresses travel only so far, usually
The MAC address is used by the network to identify which piece of hardware a packet of information is to be sent to. While the IP addresses involved indicate the original source3 and ultimate destination, a MAC address is used only on connections from one piece of networking equipment to the next.
That means when information leaves your computer, it has your computer’s network adapter’s MAC address. But when it arrives at your router, that MAC address is removed. When your router sends the information further upstream to your ISP’s router, it contains the MAC address of your router. When it moves from the ISP’s router to another router on the internet, it contains the MAC address of the ISP’s router.
And so on.
When it comes to data traveling over the network, your MAC address never makes it further than the first piece of networking equipment between you and the internet.
MAC addresses gone wild
MAC addresses, however, have been used for other things.
For example, since MAC addresses are theoretically unique, a MAC address could be used as a unique identifier for tracking the actions being taken by or on a specific computer.
The MAC addresses of the network adapters on your computer are easily readable by software running on your machine, and could be used for just about anything… except tracking your stolen laptop via its network connection.