[billpg]

Your local machine isn't on the IPv4 internet if it doesn't have a globally routable IPv4 address.

Your home router that sits on the end of a single IPv4 address would need to know about IPv4x, but in this parallel world you'd buy a router that does.

[zadikian]

"all routers on your subnet need to understand that" I thought that meant the same thing you said

[kolinko]

Of course you are, just behind NAT.

If your device has it's own public IPv4 address then you don't need IPv4x, IPv6 or whatever else.