gary on 5 Mar 2014 10:23:01 -0800

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Re: [PLUG] Using IPv6 with dynamic endpoints

=> On Tue, Mar 4, 2014 at 9:26 PM, Rich Freeman <>
=> wrote:
=> Also, it seems a bit insane that you can't have subnets smaller than a
=> /64 without breaking stuff.  We come up with an addressing scheme that
=> gives everybody an internet full of internets worth of address space,
=> and then make it impossible to subnet that because we've come up with
=> a stateless autoconfig design that requires an internet full of
=> internets worth of address space to work for a single subnet...

   FWIW, HE gives you /48 prefixes, so you have 64k networks to play with.

   In theory, VZ could assign an IPv6 address to your VZ router based on
its MAC, then route your personal /48 (or /52, or whatever) to that.
That would be stable as long as your router is the same, with no
dynamic setup needed. If your router changes, it is only a change to
the VZ route; your prefix could stay the same and your internal
networks would never know the difference. If you want a buffer between
the VZ router and your internal IPv6 network, you can burn a /64 subnet
on the link between the VZ router and your internal router, configure
the VZ router to route the rest of your prefix to the internal router,
and configure your internal router to default IPv6 traffic to your VZ
router's address. The nice thing about having 128 bits to play with is
that address space is cheap enough to throw around without having to
worry too much about running out.

   Whether VZ would do something sensible like this is another matter, but
I think the point is to try to avoid dynamic reconfiguration as much as
possible. (Well, except for RFC-3041 privacy-enhanced address
generation which randomizes the host interface address, but then you
would most likely do that on clients, not servers, so DNS addressing is
less of an issue, and routing is a non-issue.)

                                    Gary Duzan

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