Lab : Determine the MAC Address of a Host

Objective

• Determine the MAC address of a Windows XP computer on an Ethernet network using the ipconfig/all command.

• Access to the Run command.

Background/Preparation

Every computer on an Ethernet local network has a Media Access Control (MAC) address that is burned into the Network Interface Card (NIC). Computer MAC addresses are usually displayed as 6 sets of two hexadecimal numbers separated by dashes or colons. (example: 15-EF-A3-45-9B-57). The ipconfig /all command displays the computer MAC address. You may work individually or in teams.

The following resources are required:

• Windows XP workstation with at least one Ethernet network interface card (NIC)

Step 1: Open a Windows command prompt window

1. From the Windows XP desktop, click Start then Run.

b. Type cmd in the Run dialogue box then click OK.

c. A Windows command prompt window opens.

Step 2: Use the ipconfig /all command

1. Enter the ipconfig /all command at the command prompt.

b. Press Enter. (Typical results are shown in the following figure, but your computer will display different information.)

Step 3: Locate the MAC (physical) address(es) in the output from the ipconfig /all command

1. Use the table below to fill in the description of the Ethernet adapter and the Physical (MAC) Address:

Description	Physical Address
example: VIA Rhine II Fast Ethernet Adapter	example: 00-50-2C-A5-F5-73

Step 4: Reflection

a. Why might a computer have more than one MAC address?

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A computer might have more than one NIC and each NIC will have a unique MAC address. An

example of this would be a laptop that has both an integrated wireless NIC and an Ethernet NIC

b. The sample output from the ipconfig /all command shown previously had only one MAC address.

Suppose the output was from a computer that also had wireless Ethernet capability. How might the

output change?

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The MAC address of the wireless adapter will be shown in addition to the MAC address of any wired

NIC such as an Ethernet adapter

c. Try disconnecting the cable(s) to your network adapter(s) and use the ipconfig /all command again.

What changes do you see? Does the MAC address still display? Will the MAC address ever change?

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The output shows that the media (cable) has been disconnected. The IP address went away, but the

MAC address is still shown. The MAC address is designed to be permanent. It is programmed into

the NIC and is unique for each card.

d. What are other names for the MAC address?

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Other names for a MAC address include a physical address, hardware address, Ethernet address,

burned-in address, a data-link layer address, and a Layer 2 address