[arin-ppml] The role of NAT in IPv6

Roger Marquis marquis at roble.com
Mon Mar 29 14:36:46 EDT 2010

Scott Leibrand wrote:
> Leaving aside NAT-PT and v4-v6 transition for the moment, can you
> clarify how you would like to deploy NAT in an IPv6-only environment?

Substantially similar to the deployment of NAT in IPv4 environments i.e.,
a mixture of 1:1, 1:many, NAT and PAT with stateful translation for badly
designed protocols like SIP.  Why?  For the same reasons we used
non-routable addresses before NAT, privacy, freedom from external
dependencies, and certainly not least security.  IPv6 changes nothing
relevant other than the size of the address pool, but NAT did not evolve
simply to address address space shortages (though that was one of reasons
cited at the time).

Of course that's many years in the future.  We need NAT64 now and for the
duration of the transition.

Roger Marquis

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