FWIW, my old 20k-student university (a few years back) had tons of printers sitting wide open on IPv4. The university had a full /16 that was used a lot for mis

FWIW, my old 20k-student university (a few years back) had tons of printers sitting wide open on IPv4. The university had a full /16 that was used a lot for misc. computers and other equipment (no firewalls). Used to be very convenient that I could send off a few documents to print before I left home at morning, and have them waiting at the printer when I arrived at campus. Even after they added "swipe your card to print" to reduce waste, using plain old lpr to the printer IP still worked (it even cut in front of the queue, to much grumbling from the chemistry students we shared computer labs with).