I have a device that goes on the network. I need it's MAC address. There is no label on it. How do I do that? I have no access to the device itself. I can power it on and plug it in to a switch or a laptop, and that's it. There is no serial port or any other way of interfacing with the device.
To stave off the inevitable, but irrelevant, questions... we need the MAC address to "register" it on the network. Then it can get an IP address, and then "somebody else" accesses and configures it. It's a black box to us, but we have to have a MAC to register it. Yes, this is insane, but we did not design the device or decide to ship it without a label :-) Please, no responses about how this makes no sense... we know.