With iOS 14, iPadOS 14, and watchOS 7, Apple will randomize the MAC address of your iPhone, iPad, and Apple Watch every time you connect it to a new Wi-Fi network. This will help in further protecting your privacy as network operators will not be able to associate a specific MAC address to your device and then keep track of its internet activity or do any kind of device profiling.
Whenever a device joins a Wi-Fi network, it is identified on that network using its MAC (Media Access Control) address. Anyone with the right set of tools can observe the network activity and location of a device if the same MAC address is used continuously, even across Wi-Fi networks. This is where having a random MAC address is beneficial since a new MAC address is generated every time the device connects to a Wi-Fi network which makes network profiling and location tracking extremely difficult.
To reduce this privacy risk, iOS 14, iPadOS 14, and watchOS 7 include a feature that periodically changes the MAC address your device uses with each Wi-Fi network. This randomized MAC address is your device’s private Wi-Fi address for that network—until the next time it joins with a different address.
Some Wi-Fi routers might not work properly with random MAC addresses or some people might want to assign a static MAC address to their iPhone or iPad. For this, Apple is including an option to turn off the generation of a random MAC address on a per-Wi-Fi network basis as well.
Device profiling over a network is actually very common so the introduction of random MAC addresses in iOS 14, iPadOS 14, and watchOS 7 is a major step from Apple to further protect the privacy of iPhone, iPad, and Apple Watch owners.