A Snapshot of IPv6 for World IPv6 Launch Day

, June 06, 2012 Celebrate World IPv6 Launch day with facts, figures, insights and more to help you plan for that inevitable IPv6 migration.
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Do we get away from network address translation (NAT)? Not on your life. Like it or not, NAT is here to stay, and in IPv6 that means NAT66--which just translates the IPv6 address prefix and doesn't do port translation. Blogger Tom Hollingsworth has a long and detailed post, "IPv6, NAT, and the SME - A Response" on why NAT66 will be with us--despite his objections that NAT masks underlying design problems. Hollingsworth is a practical guy, and while he'd like NAT to disappear, he says he does see value in some of the use cases.

IPv6 has no notion of RFC 1918-type addresses, so each one is globally routable. The Internet Engineering Task Force quietly killed off site-local addresses, which were meant to provide address space independent of the global address space in 2004. The reasons are listed in "RFC 3879: Deprecating Site Local Addresses." That doesn't mean you're handcuffed to your carrier because of the cost of an IP renumbering. Hollingsworth points out that organizations can get provider-independent address space from the regional Internet registries like RIPE and ARIN, but it also means you need to know more about how to use them.

Luckily, Hollingsworth says, renumbering IPv6 isn't as difficult as with IPv4. "RFC 4192: Procedures for Renumbering an IPv6 Network without a Flag Day" provides a method for doing so.

Of course, you can just use NAT66 and be done with it.


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