Find Your Macintosh's Hardware Address
Are you using Windows? The Windows instructions are now here.
Hardware address is the unique fingerprint of your computer. We need this to assign a specific serial number that will not work on any other computer except yours. A hardware address is also known as Ethernet ID, Airport ID, MAC address and a few other names.
The easiest way to read your hardware address is to open FlowJo. The splash screen that is displayed when FlowJo opens shows the address.

-In OS8 or 9, you can determine the hardware address from the TCP/IP control panel. Go under the Apple menu to Control Panels. Choose TCP/IP from the list. When TCP/IP is open, go under the File menu to Get Info. The hardware address will be displayed in the dialog box.
-In OSX, you can determine the hardware address from the System Preferences dialog box:

Click on Network from within the System Preferences dialog box:

Choose the connection you're using, double click it:
For Ethernet:
For Airport:


