Changing your MAC address

If you want to increase your anonymity online, then changing your device's MAC address can help. Doing so is particularly useful if you use your device in public places like libraries and airports.

What is a MAC address?

A MAC (media access control) address, is a unique series of letters and numbers (for example, A1-B2-CD-34-5E-6F) that identifies a computer when connecting to a network. Each device (laptop, phone, smart watch, printer) is assigned a MAC address when it is manufactured.

Laptops usually have two, one that is visible when it connects to WiFi, and another when you plug in an Ethernet cable. If you sit down at a cafe with your laptop and you have WiFi enabled, the laptop will broadcast its MAC address as it searches for a WiFi network.

Your MAC address can reveal your identity

Computer manufacturers keep a list of the MAC addresses corresponding to all the devices they've built. That means buying a computer with a credit card (which is tied to your identity) makes it possible to link your purchase to a unique MAC address.

If someone decides to track your MAC address, it would be easy to trace your physical movements. This is possible because every time your computer communicates with a WiFi connection, your computer is revealing its location.

But even if directly linking you to a MAC address is not likely, it is still possible for someone to collect a series of locations and times at which your computer has connected to various WiFi networks and, in the end, connect them to you.

So what can you do to prevent this? You can change your MAC address.

How to change your MAC address

Windows

1.  Press the Windows key + X simultaneously.
2. Click on Device Manager.
3. Find Network adapters and expand the menu.
4. Look for your Ethernet or Wireless adapter and double-click to open its properties.
5. Click on the Advanced tab.
6. Under Property, scroll down the list and click on Network Address or Locally Administered Address.
7. Enter a new random MAC address under Value using the numbers 0-9 and characters A-F. The new address needs to contain 12 symbols and start with 00 (two zeros), otherwise it may not work.
8. Restart your computer.
9. Verify that the MAC address has changed: open a Command Prompt, use the command ipconfig /all and examine the Physical Address listed under the network adapter that you made the change on.

macOS

To find out your current MAC address (in case you ever want to change it back):

1. Click on the Wi-Fi icon in the menu bar.
2. Click on Wi-Fi Settings...
3. Click on the Details button located beside the connection you are connected to.
4. Click on Hardware. Your MAC address is listed here.

To change your MAC address:

1. Hold down the Option key and click the Wi-Fi icon in the top menu bar.
2. Next to “Interface Name”, make note of whether you see en0 or en1.
3. Turn off your Wi-Fi.
4. Navigate to Applications > Utilities, then open Terminal.
5. In the terminal window, type in the following command using either en0 or en1, and replace the Xs and Ys with any combination of the numbers 0-9 and characters A-F: sudo ifconfig en0 ether XY:XY:XY:XY:XY:XY
6. Hit Enter. You will need to enter your password to make the change.
7. Type your password, then hit Enter again.

Android

In Android 10, MAC randomization is enabled by default.

In Android 9, you can enable a developer option that causes the device to use a randomized MAC address when connecting to a Wi-Fi network. Here’s how to activate it:

1. Enable the developer option by going to Settings > About phone or About tablet.
2. Find the Build Number and tap it 7 times. If prompted, enter your device's unlock code.
3. Open Settings > Developer Options.
4. Enable Connected MAC Randomization under the Networking section. Note: This option is not available on all Android 9 phones and tablets.

In Android 8.0, Android devices use randomized MAC addresses only when probing for new networks.

iOS

MAC randomization is enabled by default (since iOS 8) when the device is passively scanning for Wi-Fi networks. New: iOS 14, iPadOS 14 and watchOS 7 use a different unique static MAC address for each Wi-Fi network.

Ubuntu, Debian

Use macchanger, a utility program that can automatically change your MAC address each time you attach an Ethernet cable or re-enable Wi-Fi.

To install macchanger, run the command sudo apt-get install macchanger.

During installation, you will be prompted with a screen asking if you'd like to automatically change your MAC address every time your network interface is brought up or down. Choose Yes and you're set!

Fedora

Use macchanger, a utility program that can automatically change your MAC address each time you attach an Ethernet cable or re-enable Wi-Fi.

1. Install macchanger: sudo dnf install macchanger
2. Use ip link to list the network interfaces and current MAC address. To show the currently connected interface, use ip link | grep “state UP” (wired interfaces start with eth or enp, while wireless interfaces start with wlan or wlp).
3. Switch off the network interface that you want to change the MAC address for (replacing XYZ with the name of the device from the previous step):sudo ip link set dev XYZ down
4. Set the MAC address to a random value: sudo macchanger -r XYZ
5. Switch on the network interface again: sudo ip link set dev XYZ up

If you need to restore the original MAC address, then first switch off the network interface. Use sudo macchanger -p XYZ and then switch on the interface.