Every Internet-connected device has one or more MAC addresses–-a 12-digit string that is used as a unique identifier for the device. A MAC address is not personal in itself, but very easily becomes personally identifiable when combined with other data.
MAC randomization is a feature that has been introduced on connected devices in recent years to help ensure privacy, especially when connecting devices to public wifi networks. It is most commonly used on smartphones.
Randomization conceals the real MAC address of the device and creates an artificial one that is transmitted to any surrounding wireless access points. The goal is to make it harder to track a device based on its MAC address.
Many wifi network services still rely on permanent client MAC addresses for authentication and security.
For example:
In most cases you can turn off MAC randomization for one or more specific networks, like your home wifi, while keeping the feature enabled for any other wifi networks you might connect to.
Here are the steps to turn off MAC randomization on wireless clients for different devices.
Note that depending on the manufacturer and version of operating system, some devices may have different settings or differently worded options.
Note that randomization is disabled by default in Windows, so you only need to disable it if it has actively been enabled in the past. The steps are mostly the same for Windows 10 and 11.
If randomization is generally enabled for all networks:
If randomization is turned on for one or some networks:
On Mac OS X, Mac randomization currently only applies to AirPlay and AirDrop and there are no settings to disable this.
Linux operating systems do not have MAC randomization by default and require additional packages such as the "macchanger" package on Ubuntu to enable MAC address randomization.
All operating systems use similar randomization concepts, but implement them differently, and not all randomization is equally disruptive to services.
Persistent randomization means that the client generates a single randomized MAC address per wifi network it signs into. Persistent MAC addresses are necessary for use cases such as parental controls.
These randomized addressed may be based on network profile parameters such as SSID and security type and remains the same as long as the client device is not factory reset.
Systems that use persistent randomization:
Non-persistent randomization causes the client to generate a new, randomized MAC address with every new connection. For long lasting connections, new addresses will be generated at regular intervals.
Addresses are usually fully randomized. Apple has stated that iOS generates MAC addresses that neither they themselves nor wifi manufacturers are able to predict.
Systems that use non-persistent randomization:
Article by Dr. Maghsoud Morshedi Chinibolagh and Jorunn Danielsen
https://source.android.com/docs/core/connect/wifi-mac-randomization-behavior
https://support.apple.com/guide/security/wi-fi-privacy-secb9cb3140c/web
https://help.ubuntu.com/community/AnonymizingNetworkMACAddresses