[ianburrell]

Having IPv4 host talk to IPv6 server isn't really necessary since there are enough IPv4 addresses for external servers. IPv6 is most important for client addresses to replace NAT, especially carrier-grade NAT, and simplify networks.

The article mentions NAT64, which works well for IPv6-only computers to talk to IPv4 servers. There is enough space in IPv6 to encode the whole IPv4 connection which makes stateless NAT possible.

The other mechanism is 464XLAT and MAP, where IPv4 isn't tunneled over IPv6 network, but encoded in the IPv6 address. 464XLAT is used heavily on mobile phone and uses software on the device. MAP requires support on gateway. MAP is stateless which is savings over carrier-grade NAT.