Ipv6 help

Thu Aug 27 07:33:31 UTC 2020

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 at isc.org> wrote:
> 
> 
> 
>> On 27 Aug 2020, at 15:58, Bjørn Mork <bjorn at mork.no> wrote:
>> 
>> Brian Johnson <brian.johnson at 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 at isc.org
> 