Finding a MAC Address

A MAC address is a unique number assigned to a Network Interface Card by the manufacturer, not by Duke University. You may discover your MAC address by looking for a printed label. Check the box it came in for a label. Other times, the actual NIC itself may have a sticker label somewhere on it with the MAC address. If your computer has a built-in Ethernet interface (instead of a separate NIC installed), you may find a label attached to the back or bottom of the computer displaying the MAC address. If you find a label, please make sure it really is a MAC address; the section below describes what a MAC address looks like.

Manufacturers cooperate to ensure that each address is unique. A MAC address is made of 12 hexadecimal numbers; for example 080007A92BFC (each digit is a number from 0-9 or a letter from A-F). At times, MAC addresses are separated by colons or dashes. (09:00:07:A9:B2:EB or 09-10-4A-B9-E2-A4)

Do not confuse a MAC address with an Internet Protocol ("IP") address or an e-mail address. Your Internet address ,once registered,will be provided through DHCP. An IP address is a number assigned to some computers by Duke University. An IP address looks like: 192.168.0.X

If you have not found your MAC address by the procedures above then use the table below. Choose your operating system for instructions on how to find your MAC address:

On Windows 95, 98, and ME:

• Click Start...Run
• Type winipcfg in the dialog box and hit <enter>
• Click the "Down Arrow" and select the name of your network card. The network card listed here is an ELNK3 Ethernet Adapter. Your network card will be a different brand. IMPORTANT: Be sure you do not select "Dial-Up Adapter" because a Dial-Up Adapter is for your modem connection, not your network card. If a dial-up adapter is selected, the Adapter Address will say 44-45-53-54-00-00, which is not a valid MAC address

  The "Adapter Address" is your MAC address (see illustration below)

In Windows NT, 2000, and XP:

• Click Start...Run
• Type cmd in the dialog box and hit <enter>
• Type ipconfig /all at the C:\ prompt and hit <enter>
  

The "Physical Address" is your MAC address (see illustration below)

In DOS:

• Type NET DIAG /STATUS (you must have a space after NET and after DIAG) at the C:\ prompt and hit <enter>
• Hit <enter> to examine local adapter
  

The "Permanent Node Name" is your Ethernet MAC Address (see illustration below)

In MacOS (7.5.3 or higher):

• From the Apple menu choose Control Panels and then AppleTalk
• Change the Connect via setting to Ethernet
• Click the Info button
  

The Hardware Address line contains your MAC address (see illustration below)