What’s a MAC Address, and How Do You Find It?

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Technology changes so quickly that it’s often hard to keep up or stay current. But here’s one small business networking question that’s as relevant today as it was 6 years ago, and it keeps coming up year after year: What’s a MAC address and how can I find it?

Our small business networking expert fields a reader’s question about a MAC address, and he shows you how to find it on a Windows XP desktop PC or a notebook PC.

How to Find a Mac Address on a Windows XP Desktop
PC or a Notebook PC
• Click on START, and then click on RUN
• The RUN dialogue box will appear. Type CMD and press ENTER
• A DOS window will appear. This is also commonly called a Command Prompt
• Now type IPCONFIG /ALL at the command prompt and hit ENTER. This window will now display the configuration of all of your network adapters. If you have multiple network adapters in your PC you’ll see multiple addresses. The MAC Address you’re looking for will be listed under the heading Ethernet Adapter Wireless Network Connection
• Now look for the Physical Address. It should look something like 00-50-BA-D1-BA-71
• To close the window when you are finished, type EXIT at the command prompt and hit the ENTER key

A Reader Asks: What’s a MAC Address?

A while back I saw an article of yours that described how to properly set up a secure wireless network. Based on that, I replaced my aging router with a new wireless router, and I implemented all of your security suggestions. I’m using WEP with 256-bit encryption, and I’m not broadcasting my SSID.

My router also offers something called MAC address filtering. According to the documentation, this would restrict access to the network to only the PCs that have been registered with the router. So even if someone managed to get my WEP key, they still wouldn’t be able to connect to my network.

I know what my IP address is and tried using that, but it didn’t work. Exactly what is a MAC address, and how do I find it?

Our Small Business Networking Expert Explains ‘MAC Address’ 

MAC is an acronym and stands for Media Access Control. The MAC address (also known as the physical address) is your computer’s unique hardware number. When you’re connected to the Internet from your computer (or the “host”), a correspondence table relates your IP address to your computer’s physical (MAC) address on the LAN. This is how the router knows where to send IP packets destined for your system.

On a PC or a laptop with an integrated network adapter, you need to find it using software. The process is almost identical to the utility you use to see your systems IP address. On a Windows 2000 or Windows XP machine you would use IPCONFIG. To see the MAC address, you need to add /ALL to the command.

See the bulleted box for step-by-step instructions for finding your MAC Address on a Windows XP note book or desktop PC.

Ronald V. Pacchiano is a systems integrator and technology specialist with expertise in Windows server management, desktop support and network administration. He is also an accomplished technology journalist and a contributing writer for Small Business Computing.

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