One of the newly introduced features in macOS 15 Sequoia is the ability to use private Wi-Fi addresses aka “MAC address randomisation”. https://support.apple.com/en-us/102509 By default the new setting has been changed to Rotating on new built Macs and unfortunately this does currently pose a problem when connecting to Wi-Fi networks such as eduroam.
The Private Wi-Fi Address feature offers these settings, which you can change at any time if you have administrative functionality:
Off: When set to Off, your device uses its hardware MAC address.
Fixed: When set to Fixed, your device uses a private address, but the private address doesn’t rotate, regardless of the network's security or length of time since you last joined the network. Your device chooses Fixed by default when joining a new network that uses WPA2 or stronger security.
Rotating: When set to Rotating, your device uses a private address that rotates to a different private address every 2 weeks. Your device chooses Rotating by default when joining a new network that uses weak security or no security.
Choose Apple menu > System Settings, then click Wi-Fi in the sidebar.
