Allow me to intrigue you for a moment by explaining the differences between a MAC address and an IP address. Then I’ll delineate how to locate the MAC address on your computer. I can’t simply show you how to find your MAC address in Windows without explaining what MAC addresses do and why we need them.
What’s up with MAC Addresses?
Both MAC addresses and IP addresses are unique identifiers for your computer and both play a critical role in network communications; however, there are some major differences that you should really understand. Initially you might think the two are redundant; after all, why does your computer need two distinct addresses?
Every network interface card (NIC) has a burned-in address called a Media Access Control (MAC) address. The sole purpose of the MAC address is to provide a means of delivering a package of data, called an Ethernet Frame, from one network node to another on a local LAN segment.
The key thing to understand here is that MAC addresses live in the realm of directly connected devices. If you were playing connect the dots, the MAC address is what gets you to the next, adjacent dot.
So what are IP’s for?
The internet is a motley group of hundreds of thousands of networked devices so when your computer in London tries to communicate with a web server in Palo Alto, California there’s a fairly complex set of events that need to transpire for communication to take place.
IP addresses come into play when you need to connect to a remote machine. Whenever the desired resource isn’t directly connected to your computer, you’ll need an IP address so each router along the way knows the finally destination of the data packet.
The MAC address is the thing that routers uses to get your Ethernet Frame to the next immediate step but without the IP address it wouldn’t know the ultimate destination.
Think of your MAC address like a rabbit hopping from router to router and think of the IP Address like the carrot that the rabbit is after. The carrot is sitting on a plate at the final destination and the MAC address is the thing that keeps getting you to the next device in line that separates your computer from that final destination.
When your computer tries to communicate with the Palo Alto server it first checks to see if you and the server are on the same local area network. If so, the frame is sent directly to the server and all is well; however, in most cases the server is on a different network so the computer sends the frame to the closest router in your network (called the Default Gateway) and then determines the next router to forward it to. Each router uses the MAC addresses to “carry” the frame until it arrives at the IP address of the server.
Viewing your MAC address
The above explanation is grossly simplified because there’s a lot of other components in play but it’s pretty interesting. When you have a lazy Sunday, check out Curt Franklin’s excellent tutorial on HowStuffWorks. It’ll really help you understand the nuances that I left out.
To view your MAC address in Windows, click Start and open the command prompt by typing:
In the blank black window type this:
You’ll see four columns. The one on the far left labeled Connection Name shows you which NIC you’re looking at. The Ethernet adapter should say Local Area Conn or just Ethernet as it does for me.
The third column labeled Physical Address is your actual MAC address.
Most people have multiple adapters so the screen will look busier; however, you can easily match the right MAC with the right adapter by looking at looking at the Network Adapter column.
Hope that helps!