I'm at my partner's lodgings at her university, and they use a proxy (I think, at least) running Ask4. I don't know the exact structure of their network, but it's likely to be some sort of proxy. The Ask4 service only allows 5 devices to be registered to a room at a time, however when I connected a router to an ethernet port, a page appeared stating that I'd connected a router, which would incur an extra charge.
My original plan was to spoof the MAC address of an already-registered device on the router (running DD-WRT), however this made no difference. After reading that this went against the terms of service, I thought better and removed the router.
My question is this: how can services, whatever they may be, determine what kind of device an attached MAC is? In this case, how can the proxy server determine that I've connected a router? Does it to something as naive as a
tcptraceroute, or is there a standard that I don't know about to determine device type?