Access Keys:
Skip to content (Access Key - 0)

Q: What's a MAC address and why do I need it?

On this page:

Answer

A MAC (Media Access Control) address is the unique hardware address of a network device such as an Ethernet card or a Wireless card. At MIT, the MAC address is registered and used to 'certify' users that want to use DHCP or Wireless on their computers. The MAC address information is kept in different locations depending on the operating system you are using. The address, sometimes called the physical or hardware address, is in the form of six pairs of digits separated by a colon or dash (e.g., 00:1A:22:3B:44:CD)

Macintosh OS X 10.6.x

  1. Launch System Profiler found in the Utilities folder
  2. Select the entry Network from the left column with the title Contents
  3. Highlight the appropriate entry (typically Ethernet or Airport) from the listings in the right hand side of the pane
  4. The MAC address will be found listed in the lower half of the window

Macintosh OS X 10.5.x

  1. Open System Preferences (Apple menu > System Preferences).
  2. Click Network.
  3. In the left-hand panel, select a network device (for example Built-in Ethernet or AirPort).
  4. In the right-hand panel of information for the device, click Advanced.
  5. In the subsequent window:
    • For Ethernet, click the Ethernet tab; the Ethernet ID is the MAC address.
    • For AirPort, click the AirPort tab; the AirPort ID is the MAC address.

Macintosh OS X 10.4.x

  1. Open System Preferences (Apple menu > System Preferences).
  2. Click Network.
  3. From the Show list, choose your network device.
  4. Select the appropriate tab for the device:
    • For Ethernet, click the Ethernet tab; the Ethernet ID is the MAC address.
    • For AirPort, click the AirPort tab; the AirPort ID is the MAC address.

Windows XP/Vista/7

  1. Select Start > Run.
  2. Type cmd and click OK.
  3. In the DOS window, type ipconfig /all (with a space between 'ipconfig' and '/all').
    Result: All your Ethernet devices should be listed, usually by vendor and some type of description. Your MAC address is listed as Physical Address.

IS&T Contributions

Documentation and information provided by IS&T staff members


Last Modified:

February 21, 2013

Get Help

Request help
from the Help Desk
Report a security incident
to the Security Team
Labels:
mac_address mac_address Delete
nic nic Delete
dhcp dhcp Delete
wireless wireless Delete
registration registration Delete
r-content r-content Delete
toolkit toolkit Delete
c-networking c-networking Delete
mac mac Delete
address address Delete
Enter labels to add to this page:
Please wait 
Looking for a label? Just start typing.
Feedback
This product/service is:
Easy to use
Average
Difficult to use

This article is:
Helpful
Inaccurate
Obsolete
  1. Feb 03, 2009

    There is a missing step for the Mac OS X instructions which apply to System 10.4.x. The instructions are different for Mac OS X 10.5

    1. Open System Preferences application (Apple menu>>System Preferences)
    2. Click Network.
    3. From the Show list, choose your network device.
    4. [Select the appropriate tab for the Interface. For example: Built-in Ethernet pulldown requires Ethernet tab, Airport pulldown requires Airport Tab.

    Result: Your MAC address appears in the lower left corner of the window listed as Ethernet Address or Airport ID depending on the device selected.

    The result appears in the window with a label such as "Ethernet ID" or "Airport ID", rather than in the lower left corner. The address is of the form xx:xx:xx:xx:xx:xx where the xx represent integers 0-9 and letters a-f

Adaptavist Theme Builder (4.2.3) Powered by Atlassian Confluence 3.5.13, the Enterprise Wiki