Re: I don't care what the experts say....
So, 6to4 and 4to6 obviously allow interoperability between ipv4 and v6 networks, and is pretty stable for what 15 years now? Teredo (Bleh, speak not of it and use a VPN gateway).
If you were only referring to 6to6 NAT, the best reason I have seen is client side failover or load balancing , with the HUGE caveat that you can expect some IPv6 native code to blow right up if you NAT it.
That said, since most real traffic is to services built IPv4 code, there are plenty of services that fail to notice or explode. However, unless it's sanctioned in some future version of the spec, it's still mostly useless in the real world. There have been some overseas telcos that have been doing some weird ipv6 stuff though. I think they are a bad example though, as it's not transparent, and breaks things (in addition to the spec). That said the same carriers are also doing double or triple NAT on ipv4 too.
Biting the hand that feeds IT
