IPv6-to-IPv6 Network Prefix Translation

IPv6-to-IPv6 Network Prefix Translation (NPTv6) is a specification for IPv6 to achieve address-independence at the network edge, similar to network address translation (NAT) in Internet Protocol version 4 (IPv4). It has fewer architectural problems than traditional IPv4 NAT; for example, it is stateless and preserves the reachability attributed to the end-to-end principle. However, the method may not translate embedded IPv6 addresses properly (IPsec can be impacted), and split-horizon DNS may be required for use in a business environment.

NPTv6 differs from NAT66, which is stateful. With NPTv6, no port translation is required nor other manipulation of transport characteristics. Compared to NAT66, with NPTv6 there is end-to-end reachability along with 1:1 address mapping. This makes NPTv6 a better choice than NAT66. Source : https://blogs.infoblox.com/ipv6-coe/3-ways-to-ruin-your-future-network-with-ipv6-unique-local/