So let’s say your internet provider owns x.x.x.x, it receives a packet directed to you at x.x.x.x.y.y… , forwards it to your network, but your local router has old software and treats all packages to x.x.x.x.* as directed to it. You never receive any medssagea directly to you evem though your computer would recognise IPv4x.
It would be a clusterfuck.
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.
If your device has it's own public IPv4 address then you don't need IPv4x, IPv6 or whatever else.
Your computer knows it’s connected to an old router because dhcp gave it x.x.x.x address and not x.x.x.x... so it knows it’s running in old v4 mode.
And it can still send outbound to a v4x address that it knows about.
No, it cannot, if there is a router on the way that is unaware of v4x, it will interrupt the signal.
Say your router is 1.2.3.4.0.0 in IPv4x (and 1.2.3.4 in IPv4). You are 1.2.3.4.0.1 . Someone sends you a message from outside. Your router only sees the previx of the address (1.2.3.4), and since it thinks it has 1.2.3.4, it reads the message and doesn't forward it further.
I highly recommend reading original TCP/IP RFC - it is a good tutotrial on how the IP routing works: https://datatracker.ietf.org/doc/html/rfc1180
> but your local router has old software and treats all packages to x.x.x.x.* as directed to it.
So how do you have an IPv4x address? And then how did you let someone else on the internet know about the IPv4x address?
I know plenty well how IP routing works otherwise I wouldn't be in this conversation. Is there something specific in the RFC you think I’m not understanding?