When a device successfully connects to a network, the only information the network needs is the Media Access Control (MAC) address, which can usually be found on the back of every piece of hardware:
This makes total sense, because the MAC address is unique to the device. Over time, manufacturers have been implementing creative ways to hide this address in order to make it harder to track an individual based on their device. This includes allowing a user to be able to manually change their device’s MAC address. While this is a noble effort to protect a user’s privacy, and sounds great in the marketing material, it also opens up other security holes that are difficult to fill.