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
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