IPv6-to-IPv6 Network Prefix Translation

From HandWiki
IPv6-to-IPv6 Network Prefix Translation
Communication protocol
PurposeNetwork address translation
Introduced2011; 15 years ago (2011)
RFC(s)6296, 7157...

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 IPv4 NAT; for example, it is stateless, uses a 1:1 address mapping and preserves the reachability attributed to the end-to-end principle. However, because the new address is chosen in a way that leaves the checksum unchanged (checksum-neutral mapping) the interface identifier bits change and this may break applications that embed data in them (such as IPsec). Additionally, split-horizon DNS may be required for use in a business environment.

NPTv6 multihoming example

NAT66

NAT66 was the name used in earlier drafts of the standard.[1] There were some initial proposals to rename it,[2] and a few years later the name NPTv6 was chosen.[3] One of the early versions defined two modes of operation within NAT66: a Two-Way Algorithmic mapping and a Topology Hiding Option, the latter of which used a non-reversible address mapping that would've required additional state in the translator, either in the form of a dynamic table or a statically defined set of address mappings.[4] It was soon removed, leaving the two-way mapping as the only mode of operation and making the specification fully stateless.

Current usage of the term (by vendors, in informal contexts, etc.) is unclear: sometimes it's still employed as a synonym for NPTv6[5] but often it refers to a generic implementation of stateful NAT[6][7][8] (or even full NAPT[9][10]) on IPv6.

References

  1. Wasserman, Margaret; Baser, Fred (2008-10-27), IPv6-to-IPv6 Network Address Translation (NAT66), IETF, I-D draft-mrw-behave-nat66, https://tools.ietf.org/html/draft-mrw-behave-nat66 
  2. Wasserman, Margaret; Baser, Fred (November 2008). "NAT66: IPv6-to-IPv6 NAT". p. 17. https://www.ietf.org/proceedings/73/slides/behave-14.pdf. 
  3. Wasserman, Margaret; Baser, Fred (2010-12-09), IPv6-to-IPv6 Network Prefix Translation, IETF, sec. 10.4, I-D draft-mrw-nat66-01, https://tools.ietf.org/html/draft-mrw-nat66-01#section-10.4 
  4. Wasserman, Margaret (2008-10-27), IPv6-to-IPv6 Network Address Translation (NAT66), IETF, sec. 5.1.2, I-D draft-mrw-behave-nat66-01, https://tools.ietf.org/html/draft-mrw-behave-nat66-01 
  5. "Support - 02-NAT66 configuration- H3C". https://www.h3c.com/en/d_202504/2404767_294551_0.htm. 
  6. Hogg, Scott (2021-12-28). "You Thought There Was No NAT for IPv6, But NAT Still Exists" (in en-US). https://blogs.infoblox.com/ipv6-coe/you-thought-there-was-no-nat-for-ipv6-but-nat-still-exists/. 
  7. Yuhan, Guo (2023-12-13). "What Is NAT66? Why Do We Need NAT66?" (in en). https://info.support.huawei.com/info-finder/encyclopedia/en/NAT66.html. 
  8. "NAT66 policy". https://docs.fortinet.com/document/fortigate/7.4.4/administration-guide/245279/nat66-policy. 
  9. "3 Ways to Ruin Your Future Network with IPv6 Unique Local Addresses (Part 1 of 2)" (in en-US). 2016-02-27. https://blogs.infoblox.com/ipv6-coe/3-ways-to-ruin-your-future-network-with-ipv6-unique-local/. 
  10. "NAT66: The good, the bad, the ugly" (in en-US). 2018-02-02. https://blog.apnic.net/2018/02/02/nat66-good-bad-ugly/.