generate_mac_address_mask

With cloned_mac_address setting "random" or "stable", by default all bits of the MAC address are scrambled and a locally-administered, unicast MAC address is created.

This property allows to specify that certain bits are fixed. Note that the least significant bit of the first MAC address will always be unset to create a unicast MAC address.

If the property is null, it is eligible to be overwritten by a default connection setting. If the value is still null or an empty string, the default is to create a locally-administered, unicast MAC address.

If the value contains one MAC address, this address is used as mask. The set bits of the mask are to be filled with the current MAC address of the device, while the unset bits are subject to randomization. Setting "FE:FF:FF:00:00:00" means to preserve the OUI of the current MAC address and only randomize the lower 3 bytes using the "random" or "stable" algorithm.

If the value contains one additional MAC address after the mask, this address is used instead of the current MAC address to fill the bits that shall not be randomized. For example, a value of "FE:FF:FF:00:00:00 68NMSettingWired:F7:28:00:00:00" will set the OUI of the MAC address to 68NMSettingWired:F7:28, while the lower bits are randomized. A value of "02:00:00:00:00:00 00:00:00:00:00:00" will create a fully scrambled globally-administered, burned-in MAC address.

If the value contains more than one additional MAC addresses, one of them is chosen randomly. For example, "02:00:00:00:00:00 00:00:00:00:00:00 02:00:00:00:00:00" will create a fully scrambled MAC address, randomly locally or globally administered.