Re: Ipv6 help

[Brian Johnson <brian.johnson () netgeek us>]

If an ISP provides dual-stack to the customer, then the customer only uses IPv4 when required and then will only use 
NAT444 to compensate for a lack of IPv4 address space when an IPv4 connection is required. What am I missing?

> On Aug 27, 2020, at 1:20 AM, Mark Andrews <marka () isc org> wrote:
>
>
>
> > On 27 Aug 2020, at 15:58, Bjørn Mork <bjorn () mork no> wrote:
> >
> > Brian Johnson <brian.johnson () netgeek us> writes:
> >
> > > > 1) It needs *much less* IPv4 addresses (in the NAT64) for the same number of customers.
> > >
> > > I cannot see how this is even possible. If I use private space
> > > internally to the CGN, then the available external space is the same
> > > and the internal customers are the same and I can do the same over sub
> > > ratio under both circumstance. Tell me how the math is different.
> >
> > Because NAT64 implies DNS64, which avoids NATing any dual stack service.
> > This makes a major difference today.
>
> Only if you don’t have a CLAT installed and for home users that is suicide
> at there is too much IPv4 only equipment.
>
> What really pushes traffic to IPv6 is that hosts prefer IPv6 by default.  This
> works as long as the clients see a dual stack network.
>
> And no NAT64 does not imply DNS64.  You can publish a ipv4only.arpa zone with
> the mappings for the NAT64.  There are now also RA options for publishing these
> mappings.  There are also DHCPv6 options.
>
> Mark
>
> > Bjørn
>
> -- 
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742              INTERNET: marka () isc org