I recently took an exam that covered IP6, so I was *determined* to get it working through a tunnel broker or some such means, just to say I did. I fired up test-ip6.com and...I was already on it.
My shared office had recently upgraded their modem from AT&T, which apparently supports v6 out of the box. Absolutely zero manual config on the router or client. Found out later, it's the same with Comcast where I live (northern California).
OTOH, I work at an ISP that has IP6 nowhere on its radar. I haven't raised the issue yet because I'm so new, but I have a few guesses:
- - We still have a lot of unused v4 addresses in several public
- - We are an education network, servicing only schools and school sites, so our number of clients are relatively few, and each client maybe only needs 2-3 public IPs (1 for NATing traffic, and maybe 1 or 2 for public-facing servers)
- - Potential security risk (I'm not talking about the FUD that NAT=security, I'm talking about things like the v6 flood that, well, crashes any Windows box with v6 enabled)
- - Huge cost to ensure that *every* device, server and router can handle v6, that all network staff are adequately trained, etc.
So, it comes down to huge cost with little to no appreciable gain (for our organization). Sure, routing gets simpler, no NAT overhead, but it's not like v4 is going to disappear overnight. Dual stack is the way it's going to be for a very, very long time. My grandkids may see widespread native v6. Maybe.