Finding your MAC address Source:http://198.237.39.123/inventory/instructions/mac.htm

A MAC address is a unique number that identifies a network card for network communication. This number is branded my the network card manufacturer and cannot be changed or tampered with. There can only be one unique MAC address per network card in the world!!

If you have already purchased an Ethernet network card but it has not yet been installed in your computer, open the package and look for a sticker label directly attached to either sides of the card. This label will display the MAC address as an Ethernet ID number, a MAC address number or a Physical address number. The MAC address consist of 12 digits in either 00-C0-4F-48-7A-88 or 00C04F487A48 format.

If you have an Ethernet network card installed or built-in and the network software drivers already installed in your computer, then select from below the correct option for you in order to obtain the MAC address.

Windows 95/98/ME
Run winipcfg (click on Start, then Run, then type winipcfg in the text box.) Select your ethernet card adapter (NOT the PPP Adatper), and look for a box marked Adapter Address. This is your MAC address.

NOTE: Do NOT use the "PPP Adapter" MAC address. That is your modem address! You need use the pull down menu on the winipcfg IP Configuration Window and select your network ethernet adapter. Example: 3Com 3C90x Ethernet Adapter

 Windows NT/2000
Run ipconfig /all from an MS-DOS shell window (click on Start, then Run, then type cmd in the text box.) Once the new window appears type ipconfig /all at the shell prompt. In the "Ethernet Adapter" section, look for the line that begins with Physical Address and you will see the MAC address.

 Macintosh with Open Transport
First, open the TCP/IP control panel. Select info from the main control panel. The MAC address is displayed as the hardware address.

 Macintosh with MacTCP
Open the MacTCP control panel. You should see an icon labeled Ethernet. Hold down the option key and click this icon. A number should appear beneath the icon, this is your MAC address.

 Solaris/SunOS
On Solaris and SunOS systems, the ethernet device is typically called le0 or ie0. In order to find the MAC address of the ethernet device, you must first become root, through the use of su. Then, type ifconfig -a and look up the relevant info. For example:

# ifconfig -a
le0: flags=863 &ltUP,BROADCAST,NOTRAILERS,RUNNING>
        inet 131.225.220.144 netmask ffffff00 broadcast 131.225.255.255
        ether 8:0:20:f:c2:f8

Note: Solaris and SunOS strip off the leading 0 commonly included in the MAC address. In the case of this machine, the MAC address is 08:00:20:0f:c2:f8

Linux
On Linux systems, the ethernet device is typically called eth0. In order to find the MAC address of the ethernet device, you must first become root, through the use of su. Then, type ifconfig -a and look up the relevant info. For example:

# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:60:08:C4:99:AA
          inet addr:131.225.84.67  Bcast:131.225.87.255  Mask:255.255.248.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:15647904 errors:0 dropped:0 overruns:0
          TX packets:69559 errors:0 dropped:0 overruns:0
          Interrupt:10 Base address:0x300

The MAC address is the HWaddr listed on the first line. In the case of this machine, it is 00:60:08:C4:99:AA.

 FreeBSD
On a FreeBSD machine the command dmefg will display the MAC address.

 HP
On HP systems, the ethernet device is typically called lan0. In order to find the MAC address of the ethernet device. Then, type lanscan and look up the relevant info. For example:

$ lanscan
Hardware Station        Dev Hardware Net-Interface   NM  Encapsulation      Mjr
Path     Address        lu  State    NameUnit State  ID  Methods            Num
2.0.2    0x08000935C99D 0   UP       lan0     UP     4   ETHER              52

Note: HP systems remove the :'s from the MAC address. In the case of this system, the MAC address is 08:00:09:35:C9:9D.