Anybody behind a NAT64?

[Cameron Byrne]

On Fri, Dec 7, 2012 at 2:57 AM, Tore Anderson <tore at fud.no> wrote:
> * Daniel Roesen
>
>> True dual-stack using DNS64? :) What DNS recursors do mobile handsets
>> use when both IPv4 and IPv6 PDP contexts do get established (or IPv4v6
>> for that matter)?
>
> I think that's implementation specific. Android doesn't support multiple
> PDP contexts to begin with, while my Linux laptop (using NetworkManager)
> will prefer the IPv4 DNS server (which isn't DNS64-enabled).
>
>> As far as I can see, properly supporting IPv6-only clients via
>> NAT64+DNS64 in the same... uhm... "network segment" is still an unsolved
>> problem. Still didn't find time (and motivation) to write up my approach
>> of using an EDNS "DNS64 desired" flag signalling. :)
>
> Mhm. Most mobile providers here assigns their customers public IPv4
> addresses, so use of DNS64 in a dual-stack setup would take the traffic
> through a NAT instance it could have avoided. Not optimal.
>
> That said, I'm expecting that due to IPv4 exhaustion, most of the
> providers will eventually have to switch to private IPv4 addresses +
> CGN. When that happens, avoiding DNS64 doesn't really matter all that
> much anymore, since all the IPv4-destined traffic will have to pass
> through a NAT instance either way.
>

i think the simple way to handle this is that a DNS server with a
"standard view" is available to clients over ipv4 and a DNS64 view is
available via an ipv6 address.

The network operator can control which view the customer see via the
automatic network configuration.

If the customer is dual stack or ipv4-only, push the ipv4 address of
the dns server.  If the customer is ipv6-only, push the ipv6 address
with the DNS64 view/

CB