"Virtual" Ethernet?

[MuShoo]

This is just a thought I've been mulling over, and no idea if it's even remotely technically feasible. Is it possible to set up a Teensy ++ 2.0 or a Teensy 3 as a 'virtual' ethernet device over USB? I notice that, on my mac, the USB Serial HID type will show up as a network interface, and I've been curious if it'd be possible to trick the computer into thinking there's actually an IP server/device on that connection.

Basically I want to make an ethernet device without actually using a physical ethernet connection. I wouldn't need or expect to be able to plug into a network hub/router or anything like that, but I have some ideas that would benefit from appearing as a network device to the host computer.

[PaulStoffregen]

Yes, it's possible, but this involves a LOT of difficult code. It would provide packet-level delivery, so then you'd need to build protocols on top of it. ARP, UDP, DHCP, DNS, ICMP are fairly simple. TCP is much more complicated....

[MuShoo]

That's (most likely) fine. Like I said, this is a ways off, but I may need to reverse engineer an ethernet-based protocol and shoehorn support for it into a pre-existing product (which has no ethernet jack, just USB). Worst case, I make a little inline adapter box that takes USB and spits out ethernet, or possibly just a piece of software you run on your computer. But good to know that the possibility is there! Whether I could make it fit into an already somewhat hefty Teensy ++ 2.0 sketch (36kb sketch size, ~3k of RAM in use, so there's certainly room) is another step for much much later.

Thanks!