@CH23: You can try
this USBNet script to see if that works as expected.
(NOTE: if you don't have FBInk installed, either comment out the fbink calls, or remove the "-e" flag from the shebang to prevent that from making the script abort early).
(NB: It follows the Kindle USBNet setup in terms of MAC/IP, which may not be what you're used to/expecting).