Finding a Computer's MAC Address on the Network

Last updated: Apr 14, 2008

Sometimes we need to know the MAC address of a specific computer for multiple reasons. For example, I needed to know the MAC address of one of my computers so I could tell the router to assign a specific IP address via DHCP. Another reason you need to know the MAC address is so you can block a specific computer from talking to you. Maybe you need to know the MAC address so you can allow only that computer to communicate with you. There are many reasons for knowing a MAC address of a computer. Some reasons good other times it is used with bad intentions. Like port sniffing packets with a specific MAC address.

You may say well thats easy a simple ipconfig (on windows) or ifconfig (linux) will tell me the MAC address of my NIC. Well you are right, but sometimes it is not feasible or efficient to physically check the MAC address. This is why I will show you how you can use nmap or nbtstat to determine the computer’s MAC address remotely.

To find the MAC address and other interesting information on a remote IP or hostname use the following command:

nmap -Av -T4

Look for the line that says MAC address. Be careful when port scanning most of the time it will set off IDS (Intrusion Detection Systems) and your IP address will be logged. So, port scan only computers you own.

If the computer is on your same network you can use this command from windows:

nbtstat -a

I believe this only works if they have netbios enabled

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