A note for Windows home networking users:
On the connection facing the Internet, firewall access to ports 137, 138, 139 and 445
People who use vendor provided modem/routers (such as cable and aDSL boxes) should check if those ports are firewalled in-bound from the outside world.
Note: Most communication vendor's supplied boxes are shipped with that block already installed, since these are among the most popular attack vectors.
Note2: The client (Kindle) is already firewalled against these ports in-bound.