Navel Gazing at NAT in IPv6

Why It Matters

Without standardized, vendor‑supported IPv6 NAT mechanisms, enterprises struggle to achieve reliable multi‑homing and redundancy, hindering broader IPv6 adoption and increasing operational costs.

Key Takeaways

• NAT66 remains controversial despite limited practical use cases
• MPTV6 experimental draft offers prefix translation but lacks standardization
• Multi‑homing without BGP drives demand for IPv6 NAT solutions
• Inconsistent provider prefix sizes hinder scalable NAT66 implementations
• Vendor support for NAT66/NPTv6 in SOHO gear is currently minimal

Summary

The IPv6 Buzz episode tackles the contentious topic of Network Address Translation in IPv6, focusing on NAT66 and the experimental MPTV6 prefix‑translation draft. Hosts Ed Orly, Nick Baraglio, and Tom Coffeen explore why translating from IPv6 to IPv6 is considered a “third rail” despite real‑world pressures from large enterprises and federal customers.

They trace the history of a NAT66 draft from the early 2010s that never progressed beyond draft‑00, and contrast it with MPTV6, which survived as an experimental specification. Use cases such as dual‑provider TV/voice services, multi‑homing without BGP, and the need to reconcile mismatched provider prefixes (e.g., /60 versus /52) are highlighted as drivers for NAT66‑style solutions. The hosts argue that BGP, while technically correct for multi‑homing, is financially and operationally prohibitive for most organizations, especially at scale.

A memorable example quoted from Dan Wing’s 2010 Google IPv6 implementers talk illustrates how longest‑prefix‑match can misroute traffic when a customer holds two distinct provider prefixes, necessitating address translation to force the correct outbound path. The discussion also points out the lack of a unified standard for varying prefix sizes and the fragmented vendor implementations of NAT66/NPTv6 in small‑office/home‑office equipment.

The panel concludes that without a clear IETF standard and broader vendor support, enterprises will continue to face a “structural gap” when trying to achieve IPv6 redundancy and multi‑homing. This gap could slow IPv6 adoption, push organizations toward costly BGP deployments, or force reliance on ad‑hoc NAT solutions that may not scale, underscoring the urgency for a coordinated industry response.

Original Description

Ed, Nick, and Tom discuss the need for Network Address Translation v6 to v6 (NAT66). While Network Prefix Translation (NPTv6) exists, its limitations make it insufficient for real-world business needs. They also highlight that without a standardized NAT66, the market is forcing vendors to implement their own, hindering widespread IPv6 adoption.

Links:

IPv6-to-IPv6 Network Address Translation (NAT66) - https://www.ietf.org/archive/id/draft-mrw-nat66-00.html

RFC 6296: IPv6-to-IPv6 Network Prefix Translation - https://datatracker.ietf.org/doc/rfc6296/

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