How to Harness the Power of Open Source – Welcome to the World of Ubuntu

How to Check the MAC Address on Ubuntu | A Step-by-Step Guide for Command Line and GUI

Basics of Ubuntu
佐川 直弘 | Naohiro Sagawa
By 佐川 直弘 | Naohiro Sagawa (運営者)
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目次

1. What is a MAC Address?

Overview of MAC Addresses

A MAC address (Media Access Control address) is a unique identifier assigned to a network interface card (NIC). This address is essential for device communication on a network, as each network device has its own unique MAC address. A MAC address is 48 bits long and is typically represented in the format “MM:MM:MM:SS:SS:SS.”

Roles of a MAC Address

MAC addresses primarily serve the following functions:

  • Network Communication: Enables communication between devices at the data link layer, ensuring accurate data transmission.
  • Security Management: Used by network administrators to allow only specific devices to connect to a network.
  • Troubleshooting: Helps identify specific devices when network issues arise.

When is a MAC Address Needed?

A MAC address is required in the following situations:

  • Registering a new device on a network.
  • Diagnosing network connection issues.
  • Assigning a specific IP address to a device.

2. How to Check the MAC Address on Ubuntu: Command Line Methods

2.1. Checking the MAC Address Using the ip link Command

One of the simplest ways to check a MAC address on Ubuntu is by using the ip link command. Follow these steps to find the MAC address of your network device:

  1. Open the terminal.
  2. Enter and execute the following command:
ip link show

The output will display network device information. The hexadecimal value following “link/ether” is the MAC address.

Example:

2: wlp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether f8:6a:3f:4b:b0:ab brd ff:ff:ff:ff:ff:ff

2.2. Checking the MAC Address Using the ifconfig Command

Another method is to use the traditional ifconfig command. Follow these steps:

  1. Open the terminal.
  2. Enter the following command:
ifconfig

The MAC address will be displayed after “ether.”

Example:

wlp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    ether f8:6a:3f:4b:b0:ab  txqueuelen 1000  (Ethernet)

2.3. Extracting the MAC Address Using grep

To extract the MAC address of a specific network interface more easily, you can use the grep command:

ip addr | grep "link/ether"

This command filters out unnecessary information, displaying only the MAC address.

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3. How to Check the MAC Address Using the GUI

Using Ubuntu’s Network Settings

Checking the MAC address using the GUI is a convenient option for users who prefer not to use the terminal. The following steps apply to the GNOME desktop environment:

  1. Open the Settings Menu
    Open the “Settings” menu in Ubuntu.
  2. Access Network Settings
    Select “Network” from the left-hand menu.
  3. View Network Connection Details
    Click on the settings (gear) icon for your Wi-Fi or wired connection to view detailed information. The MAC address will be displayed as “Hardware Address” or “MAC Address.”

Screenshot Examples

The settings screen should look similar to the examples below:

MAC Address

 

MAC Address
  • For Wi-Fi connections: Select “Wi-Fi” from the left menu and click the gear icon.
  • For wired connections: Select “Wired” and follow the same steps to check the MAC address.

4. Important Considerations When Checking a MAC Address

4.1. Multiple Network Devices

A computer may have multiple network interfaces, such as Wi-Fi, Ethernet, and Bluetooth. Each interface has a unique MAC address, so it’s important to check the correct MAC address based on your needs.

4.2. Checking the MAC Address of a Bluetooth Device

To check the MAC address of a Bluetooth device, use the following command:

hciconfig

The “BD Address” in the output is the MAC address of the Bluetooth device.

Example:

hci0:    Type: Primary  Bus: USB
    BD Address: DC:41:A9:FB:7A:C4  ACL MTU: 1021:4  SCO MTU: 96:6

5. Frequently Asked Questions (FAQ)

Can a MAC Address Be Changed?

Normally, a MAC address is a device-specific identifier and cannot be changed permanently. However, on Linux, you can temporarily change your MAC address using the ip link command:

sudo ip link set dev eth0 address XX:XX:XX:XX:XX:XX

How Can I Check the MAC Address in a Virtual Environment?

Virtual machines (VMs) also have unique MAC addresses assigned to each network interface. You can check the MAC address from your VM software’s network settings menu or by running the ip link or ifconfig command inside the virtual machine.

6. Conclusion: Mastering MAC Address Checking on Ubuntu

We have covered two main methods for checking a MAC address on Ubuntu: using the command line and using the GUI. Both methods are easy to follow and useful for network management and troubleshooting. The next time you need to identify a device on your network or diagnose a connection issue, refer to these steps to find the MAC address quickly and efficiently.

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