Ah, do you happen to have a handy reference for the specifics (i.e. which versions of which operating systems)?  I hadn't realized some degree of sanity had prevailed.

-ewemoa (September 05, 2015, 07:04 PM)

Sadly, the only reference I have handy at the moment is a rather dryly written college text book sitting on my bookshelf. I can tell you that all versions of Windows have "let's naively use the MAC address to create our IPv6 address!!" disabled by default and I believe the setting is buried far enough in either the registry or the group policy editor that someone would have to set out with the purpose of enabling it. It's definitely not where the casual user will inadvertently activate it.

Looks like a dang good deal, but digging around on the SitePoint site it appears that most of their stuff is heavily centered around web design. That's not really my wheelhouse.

ewemoa, when the IPv6 specification was originally drawn up, the bright idea was to incorporate a device's MAC address into the creation of the allocated IPv6 address. This was back before we knew what we know today so along the lines someone got smart & designed a smarter, better way to create those addresses and this is the preferred method used today.

Modern OSes all use this newer method, but that older method is still in the code, but disabled, for compatibility and fail-safe purposes if it's ever needed...or someone's nutty enough to want to use it.

As for NAT, a lot of us old-timers have always seen it as as security feature, but honestly, the days of it helping secure one's network or machine has past. NAT on its own is just a convenience feature these days that allows one to use multiple devices through one IP address. NAT, on its own, is easily circumvented by script monkeys as its design focus was never security.

With IPv6 there's no need to share IP addresses among devices so that's why it's going away. NAT is no substitute for a firewall and even when used in conjunction with a firewall should only be seen as a feature of convenience rather than an additional layer of security. A good hardware firewall at the entrance to your network and a good software firewall on each machine is what will be needed with IPv6 just as it's needed with IPv4. The only difference is NAT won't be needed (or desired) anymore.