Can a MAC address be traced?

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Summary: A MAC address can easily be traced for as far as it travels. The problem is a MAC address doesn't travel far enough to be useful.

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You're correct ... it could put a big dent in laptop burglaries if MAC addresses were traceable. Or it would at least increase the odds of stolen equipment being recovered.

But they're not. At least, not in any way that could help.

Let's look at why.

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A MAC, for "Media Access Control" address is a unique number that's assigned to every ethernet network interface.

In theory, it's unique anyway. 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 that they're unique, so multiple network interfaces can in fact have the same MAC address.

• The MAC address can be set in software in many network interfaces, meaning that whatever the original MAC address, it can be overridden later.

So the uniqueness that we might want to rely ... can't be relied on.

But that isn't really the biggest problem.

The MAC address is used by the network to identify which piece of hardware a packet of information is to be sent to. In other words, it's used only on connections from one piece of networking equipment to the next.

That means that when information leaves your computer it has your computer's MAC address, but when it arrives at your router that MAC address is removed. When the information is sent by your router further upstream to your ISP's router, it contains the MAC address of your router. When it moves from the ISPs router to another router on the internet, it contains the MAC address of the ISPs router.

And so on.

Your MAC address never makes it further than the first piece of networking equipment between you and the internet.

There are various alternative solutions that you might want to look into for stolen laptop recovery. While not all survive a reformat of the machine, many thieves actually try to connect a stolen laptop as-is in order to recover or steal the data thereon as well, at which point these tracing tools kick in.

And, of course, you'll want to make sure that the data on your laptop is secure no matter what.

Related:

• How can I keep data on my laptop secure? Laptops are portable, convenient and easily lost. When lost all the data could easily be available to the finder. Encryption is the answer.

• What's the difference between a Mac Address and an IP Address? MAC and IP addresses are both key components to network, but they serve different purposes, and are visible in very different ways.

• What's the difference between a Mac Address and an IP Address? MAC and IP addresses are both key components to network, but they serve different purposes, and are visible in very different ways.

Article C3635 - January 24, 2009