Can I trace a MAC address?
Hi, everyone.
Leo Notenboom here for askleo.com
Here's the question.
I know that all computers have a unique MAC address, but how traceable are they? If
my laptop gets stolen and I know my MAC address, can I get it back
If the person stole it gets connected
to the Internet even after formatting the Machine and thinking that it's safe
to connect, seems like this could stop laptop burglaries.
If that MAC address thing is traceable. You are correct.
It would put a big dent in laptop theft
If MAC addresses were traceable, the way you describe, as you note,
there has not been a big dent in laptop theft,
because while MAC addresses are traceable kind of, they're not traceable that well
or that way. Let me explain a little bit about why that is and why people hanging
on to MAC address as some kind of a hope really shouldn't be.
A MAC address is supposed to be unique.
It stands for Media Access Control address, and it's a 48 bit number,
if you will, that is assigned to every network adapter.
And in theory,
every single network adapter should have a unique a globally,
literally planetary unique ID that is used only for that specific network adapter.
So what that means is that, yes, your laptop.
My laptop has a unique MAC address that is
different or supposed to be different than every other MAC address on the planet.
It applies to any network adapter, and by that, I mean not just an Ethernet
connector that you could plug into the MAChine, but a WiFi connection as well.
And in fact, if your MAChine has multiple
Ethernet connections or has an Ethernet connection and a WiFi connection,
it will have multiple MAC addresses, one for each of those adapters.
Now, there are two things that get in the way of it being truly globally unique.
One is that manufacturers are supposed to make them unique.
Some don't.
Some just don't follow the rules they're supposed to.
I don't know that there's an enforcing body, but the fact is that occasionally
a manufacturer will make multiple network adapters that have the same MAC address.
Not supposed to be,
but they can. The other and is perhaps a more pragmatic problem with the issue
is that especially in modern computers, you can change your MAC address,
usually deep in the bowels of your network settings.
There's an option for you to actually define your own MAC address,
which would overwrite whatever hardware assigned MAC address your adapter has.
That's something that people in the know.
Perhaps hackers could use.
If this were truly a threat,
they could set up a completely unique MAC address that had nothing to do with what
you thought the MAC address was and therefore slide under your radar.
The real problem, though,
is that MAC addresses don't travel as far as you think they do.
When we think of addressing
We think of IP addressing.
Internet protocol addressing.
And indeed, every device connected
to the Internet is supposed to have a unique Internet protocol address.
They do. My router has an IP address here at home.
It is unique from every other device connected to the Internet.
That's how the Internet works.
It knows how to send data from one IP address to another.
But at the next layer down,
that trip for that data that's going from one IP address to another can
actually travel across multiple different pieces of hardware.
That's where the MAC address comes in.
So, for example, when a server is sending
my computer a packet of data, it sends it to a router.
That router sends it to another router.
That router may send it to another and another, and not until finally reaches
my router, at which point it then gets sent on to my MAChine.
Each of those routers has a unique MAC address, and that's how the data is sent.
The server says, here's a packet with information destined for this IP address.
I will now send it to the router at this MAC address.
That router then says, okay,
this needs to get forwarded on to this router over at that MAC address.
The next router says it goes off to the router at this other MAC address.
So the MAC address is used for direct equipment to equipment communication,
not the logical server to MAChine communication.
What that means, though, is that the originating MAC address
doesn't travel beyond the first connection.
In other words, the server which has a MAC
address, sends the data to the first router, which says,
I got this packet of data from this MAC address, but that's it.
It then loses that information as it
forwards the packet on to the next router in the chain.
So as a result, what that means is that just normal
Internet traffic doesn't contain the MAC address you're looking for.
At best, it contains the MAC address
of the closest router upstream that sent you your data,
but that's it. That will not get you all the way back to the machine originating
the data, and more importantly, it won't get you to your laptop.
Now, there is one other thing that can happen, and this one is kind of odd,
but you'll notice that in Windows, you can see your MAC address.
By definition,
there are a couple of different interfaces that will allow you to see what the MAC
address is for each of your network adapters.
If you can see it, software can see it.
If software can see it, it could use it for things, right.
In fact, it may be a piece of information
that gets bundled up by a website to kind of sort of uniquely identify your computer
as it goes about happily tracking things across the Internet.
That's something that a we can't really control.
We don't really control.
But B, it's not used consistently enough.
And in a way that would allow us to specifically track up MAChine again.
It's tracking kind of a network adapter,
but what happens with it is truly, really unclear.
And to be honest, they may not be using this technique.
They may be using other techniques, but the bottom line is
that the information is available to the software running on your MAChine.
Who knows what that software is doing
with it, using it in a way to track where your machine happens to be.
Unless you've got tracking software
installed and there are various services that will do that.
There's nothing you can do.
There really isn't any way to use a MAC
address in the way you would really like to.
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20452 I'm Leo Notenboom and this is askleo.com.