Lab - Determine the MAC Address of a Host

Lab – Determine the MAC Address of a Host Topology Addressing Table Device PC Interface VLAN 1 IP Address 192.168.1.2 Subnet Mask 255.255.255.0 Objectives • Determine the MAC address of a Windows computer on an Ethernet network using the ipconfig /all command. • Analyze a MAC address to determine the manufacturer. Background / Scenario 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. Required Resources PC running Windows 10 with at least one Ethernet network interface card (NIC) Connectivity to the Internet Part 1: Locating the MAC Address on a Computer In this part of the lab, you will determine the MAC address of a computer using the Windows ipconfig command. Step 1: Open a Windows command prompt window Right-click on the Start button and select Command Prompt. Lab – Determine the MAC Address of a Host Step 2: Use the ipconfig /all command Enter the ipconfig /all command at the command prompt. 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 Use the table below to fill in the description of the Ethernet adapter and the Physical (MAC) Address: Description Wireless LAN adapter Local Area Connection* 1 Physical Address 24-41-8C-45-3E-A5 Lab – Determine the MAC Address of a Host Wireless LAN adapter Local Area Connection* 2 26-41-8C-45-3E-A4 Wireless LAN adapter Wi-Fi 24-41-8C-45-3E-A4 How many MAC addresses did you discover in your PC? 3 Part 2: Analyzing the Parts of a MAC Address Every Ethernet network interface has a physical address assigned to it when it is manufactured. These addresses are 48 bit (6 bytes) long and are written in hexadecimal notation. MAC addresses are made up of two parts. One part of the MAC address, the first 3 bytes, represents the vendor who manufactured the network interface. This part of the MAC is called the OUI (Organizationally Unique Identifier). Each vendor who wants to make and sell Ethernet network interfaces must register with the IEEE in order to be assigned an OUI. The second part of the address, the remaining 3 bytes are the unique ID for the interface. All MAC addresses that begin with the same OUI must have unique values in the last 3 bytes. In the example shown in the lab, the physical MAC address for the Ethernet LAN interface is D4-BE-D9-136300. Manufacturer OUI D4-BE-D9 Unique Identifier for the Interface 13-63-00 Vendor Name Dell Incorporated Step 1: List MAC addresses discovered by you and your classmates in Part 1, Step 3a. List the 3-byte Manufacturer OUI and the 3-byte unique interface identifier. You will fill in the Vendor name in Step 2. Manufacturer OUI D4-BE-D9 Unique Identifier for the Interface 13-63-00 Vendor Name Dell Incorporated 24:41:8C Intel Corporate Step 2: Lookup the vendors who are the registered owners of the OUI that you listed in the table. a. Wireshark.org provides an easy to use lookup tool at https://www.wireshark.org/tools/oui-lookup.html. Use this tool, or use the Internet to search for other ways to identify an OUI. Lab – Determine the MAC Address of a Host b. Use the information that you found to update the vendor column in the chart in Step 1a. How many different vendors did you discover? __________________________________________ Reflection 1. Why might a computer have more than one MAC address? _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ 2. 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? _______________________________________________________________________________________ _______________________________________________________________________________________ Lab – Determine the MAC Address of a Host _______________________________________________________________________________________ 3. Try connecting and disconnecting the network cable(s) to your network adapter(s) and use the ipconfig /all again. What changes do you see? Does the MAC address still display? Will the MAC address ever change? _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________ 4. What are other names for the MAC address? _______________________________________________________________________________________ _______________________________________________________________________________________ _______________________________________________________________________________________