[throw0101b]

> I can't `ping ::ffff:192.168.0.1` and have it ping my router.

How would that even work in theory?

How would a ('legacy'?) host that only understands the 32-bit data structure of IPv4 addresses talk to a >32-bit data structure IPv6 addressed host?

[rnhmjoj]

You need a translator, i.e. a middle host with dual IPv4/IPv6 stack that can convert an IPv4 packet to an IPv6 packet and v.v. By the way, it's not just theoretical, it exists and it has been standardised, see https://nicmx.github.io/Jool/en/intro-xlat.html#ipv4ipv6-tra...

[FuriouslyAdrift]

If it truly encapsulated IPv4, then there wouldn't be two stacks. It would be one stack and legacy devices could snip the xtra bits (or have it done for them via a router).

[icedchai]

I'm skeptical. How would the legacy device V4 understand the "extra bits"? How would this work on the same subnet (no router)?

[FuriouslyAdrift]

If it can't natively (by creating a new networking stack), then a router would have to re-write the packet.

Endpoint dvices should not be direct peering (security). Always go through either a passthrough inspection device or router.

[icedchai]

Endpoint devices peering directly is how things work on most small networks. What you describe would cause more problems than it solves.

[growse]

> (or have it done for them via a router)

And then we are back to NAT...