My network admin might have a record of my default MAC address tied with some mischievous doings as well as my currently used address that they've likely collected after I started accessing using their controlled logins. I initially thought that they would not be able to trace the activities back to me. However, I've recently noticed that only the school's machines can use Ethernet to access the network and that the identification process most likely has nothing to do with MAC addresses, since changing one of the machine's defaults and using one of those on mine produced the same results. Ethernet recognizes the school's machines but not mine.
What other possible ways are there to uniquely identify machines, aside from reading their MAC addresses?