Iljitsch van Beijnum writes: > In the multi6 (multihoming in IPv6) working group, as one of many > proposals, we've been looking at putting a 64 bit host identifier in > the bottom 64 bits of an IPv6 address. If such a host identifier is > crypto-based (ie, a hash of a public key) then it is possible to > authenticate a host at any time regardless of where the host connects > to the network at that particular time and without the need for a PKI > or prior communication. This is precisely the kind of mistake that will exhaust the entire IPv6 address space just as quickly as the IPv4 address space. Don't engineers ever learn from the past?