Synthesize DNS64 AAAA answers only under the defined A-record conditions

Treat this document as a focused evidence review: Synthesize DNS64 AAAA answers only under the defined A-record conditions. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 6147 — DNS64: DNS Extensions for Network Address Translation from IPv6 Clients to IPv4 Servers from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• By default, DNS64 must not synthesize AAAA records when usable, non-excluded AAAA records already exist. The research record locates this support at Sections 5.1.1 (The Answer when There is AAAA Data Available) and 5.1.4 (Special Exclusion Set).
• After an empty AAAA answer, DNS64 queries for A records and synthesizes AAAA records only when one or more A records are returned. The research record locates this support at Section 5.1.6 (Data for the Answer when Performing Synthesis).
• A validating DNS64 must authenticate the negative AAAA answer before querying A records, preventing synthesis from bypassing a legitimate AAAA record protected by DNSSEC. The research record locates this support at Section 5.5 (DNSSEC Processing: DNS64 in Validating Resolver Mode).

Do not import neighboring assumptions into the source record. The supported task is a scoped comparison involving authoritative zones, delegations, resolvers, caches, record owners, and the clients that consume the resulting answers and the conditions the source actually describes.

What the source does not establish

This RFC evidence supports only the named DNS protocol decision; it does not prove Windows implementation support or a safe production configuration. No current deployment state or change approval follows from the source alone. Validate Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state, and treat examples or options as conditional inputs rather than defaults.

Applicability questions

• For source statement 1 at Sections 5.1.1 (The Answer when There is AAAA Data Available) and 5.1.4 (Special Exclusion Set), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 5.1.6 (Data for the Answer when Performing Synthesis), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 5.5 (DNSSEC Processing: DNS64 in Validating Resolver Mode), which observable configuration, record, or test can confirm applicability here?
• Within authoritative zones, delegations, resolvers, caches, record owners, and the clients that consume the resulting answers, which versions, roles, and configuration states define the review population?
• Could Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state invalidate the test, hide a failure, or change applicability?
• Who owns the decision, and which observation requires stopping, escalation, or rollback?

DSE recommendation:

DSE recommends using the cited source as the evidence anchor for this decision. Use a two-person review for the source interpretation and the resulting operational decision. Record the source location, examined part of authoritative zones, delegations, resolvers, caches, record owners, and the clients that consume the resulting answers, observed and expected states, owner, and reason for deviation.

Translate the conclusion into change control only after documenting dependencies, impact, test method, expected signals, failure signals, and restoration steps. Include Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state, while excluding secrets and sensitive personal or topology data from ordinary tickets.

Verification and evidence

Tie each conclusion back to Sections 5.1.1 (The Answer when There is AAAA Data Available) and 5.1.4 (Special Exclusion Set); Section 5.1.6 (Data for the Answer when Performing Synthesis); Section 5.5 (DNSSEC Processing: DNS64 in Validating Resolver Mode) and to observable material such as zone data, packet captures, query transcripts, delegation checks, resolver configuration, and negative-answer behavior. Preserve provenance and stable identifiers without copying secrets into the evidence set.

Retain the starting state, authorization, execution record, outcome, deviation, and final state as one review package. Move disruptive checks to an approved test path. Reopen the decision when versions, design, dependencies, ownership, or official guidance changes.

Official references

• RFC 6147 — DNS64: DNS Extensions for Network Address Translation from IPv6 Clients to IPv4 Servers — RFC Editor / Internet Engineering Task Force