Comment by mahboi
13 hours ago
6to4 and NAT64 are not what I'm saying. Those involve a relay server and v4 translation, and there's an entire memo on why that's unreliable and abandoned. I want to switch to fully native IPv6 without changing any of my addresses. There's no reason this should be impossible.
> I want to switch to fully native IPv6 without changing any of my addresses. There's no reason this should be impossible.
… except for the fact that you have to have completely new data structures and packet format to fit more address bits, and once you change the structures you need a new version field so any gear that sees a packet knows where to use the old code paths or new ones.
Then you're at the point where you have to push new code everywhere to handle these changes, and some nodes will have only the old code and some the new code, so now you're into translation and/or tunnelling to make sure the old addresses can talk to new addresses. Depending on their risk tolerance, some operators will enable the new code and some will not.
You also have to update DNS with new records, as A records are hard-coded to 32 bits. So now you're updating DNS libraries and user land.
There is no way to expand address space without going through all the same issues as what we call "IPv6" (originally SIPP) has gone through.
* https://github.com/becarpenter/misc/blob/main/why6why.md
I know. All these things were possible and completed for IPv6, but that's only part of the battle. The rest is making it easy for users at various levels to migrate. IPv6 didn't do that, that's why we're stuck in today's situation.
There's no requirement to change DNS upfront if your IPv6 addresses are 32-bit. V6 translation to/from v4 should be doable at any hop instead of relying on a flaky anycast relay. You shouldn't need a different DNS or DHCP server for IPv6 either, only one that supports both protocols (also shouldn't be forced to use SLAAC). I want the minimum initial migration to just be a toggle to use v6 with your old v4 address, not a full network restructuring upfront.
IPv6 also had an upfront requirement to change all existing routes, which is huge. That shouldn't even be needed in the final step. It should just be that people start using longer addresses given that both ends are v6. Even still there should be no requirement for every hop along the route to be v6, only the ones that go deeper than /32 near the ends.