the.com/mac addresses
the burned-in serial number that makes your laptop unmistakably itself on any network.
means a 48-bit hardware identifier assigned to a network interface so devices on the same local network can find each other.
from born with ethernet at xerox parc in the 1970s, standardized by ieee, which still hands out address blocks to manufacturers like a hardware dmv.
formatsix pairs of hex digits, like 00:1a:2b:3c:4d:5e
first halfidentifies the manufacturer, not the device
randomizationphones now fake macs to dodge tracking
not routableuseless beyond your local network segment
for instance
apple oui blocks — apple owns thousands of prefixes like 3c:15:c2
wifi tracking scandal — retailers tracked shoppers via mac in the 2010s
ios 8 randomization — apple 2014 update scrambled macs during wifi scans