Most consumer-grade NICs have a default MAC address which is retrievable with device drivers, but delegate (Ethernet) packet assembly to the OS. If the OS asks the NIC to emit a packet, then the NIC often receives the packet as a blob, DMA'd from main memory, and emits the bytes as octets. Other NICs do manage packet assembly, but allow overwriting the default MAC address. By the time I was learning Linux, we had GNU MAC Changer available in userland with the macchanger command, and many distros have configuration for randomizing or hardcoding MAC addresses upon boot.

I want to say that this is all because olden corporate network management policies could require a technician to replace a NIC without changing the MAC address, but more likely it is because framing and packet assembly was not traditionally handed to a second controller, and was instead bit-banged or MMIO'd by the CPU.

[–] FlexibleToast@lemmy.world 15 points 1 year ago (1 children)

Some devices, like Android, do this automatically. By default they have randomized mac enabled.

[–] madcaesar@lemmy.world 4 points 1 year ago (3 children)

Where is this setting?

[–] Richie030@unilem.org 3 points 1 year ago

You likely have it enabled by default, it's located in the view more or advanced settings on each specific wifi network, once enabled just forget network and reconnect, if that doesn't work, you can try enabling "WiFi non-persistent MAC randomisation". I'm not techie but that's what I did whilst on a camp site with a 30 minute trial, worked a beaut.

[–] 0x2d@lemmy.ml 3 points 1 year ago

https://files.catbox.moe/zyrnw1.png

[–] vithigar@lemmy.ca 2 points 1 year ago

Can't speak for other devices, but on my Samsung it's a network level setting in the "view more" section of the wifi network configuration.