[throw0101a]

> My ISP didn't also give me 2002:70.94.201.31 or whatever.

Traffic to 2002:70.94.201.31/48 is tunnelled via 70.94.201.31 with-in an IPv4 packet (encapsulation):

* https://en.wikipedia.org/wiki/6to4

[zadikian]

I mentioned 6to4 in the original comment. It doesn't fulfill this use case, it still relies on v4 packets.