Re: @boxplayer - "Nobody uses it..."
IPX was never an Internet protocol, just a LAN one. The actual transition was from ARPANET's NCP to TCP/IP. Since there were relatively few nodes at the time, the Defense Communications Agency simply set a mandatory "flag day" when NCP would stop being routed. Even that wasn't a total success; it was initially supposed to be January 1, 1983, but they had to give a three month extension because not everyone had successfully written TCP/IP stacks by then.