NAT exists in IPv6:
- IPv6-to-IPv6 Network Prefix Translation exists (RFC 6296, June 2011).
NATing between IPv6 and IPv4:
- Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers (RFC 6146, April 2011)
- Mapping of Address and Port using Translation (MAP-T) (RFC 7599, July 2015)
Delivering a virtual IPv4 link over IPv6:
- Dual-Stack Lite Broadband Deployments Following IPv4 Exhaustion (RFC 6333, August 2011)
- 464XLAT: Combination of Stateful and Stateless Translation (RFC 6877, April 2013)
- Mapping of Address and Port with Encapsulation (MAP-E) (RFC 7597, July 2015)
As for firewalls see:
- Recommended Simple Security Capabilities in Customer Premises Equipment (CPE) for Providing Residential IPv6 Internet Service (RFC 6092, January 2011)
- Thousands of ISP’s are using these RFCs to deliver working IPv4 and IPv6 to their customers today. Often the customer doesn’t even know they are using them.
If you don’t want to do a forklift upgrade deploy routers which support these RFCs as the old ones die and slowly migrate to a IPv6-only IPV4AAS model. Nobody has ever said that forklift upgrades where required.
Seen 2021/09/14 mailing list