Anybody behind a NAT64?

[Tore Anderson]

* 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.