Require transparent DNS proxy behavior through broadband gateways

Treat this document as a focused evidence review: Require transparent DNS proxy behavior through broadband gateways. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 5625 — DNS Proxy Implementation Guidelines from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• A simple gateway DNS proxy should forward the complete request and response verbatim so new extensions behave as if the proxy were absent. The research record locates this support at Section 3 (The Transparency Principle).
• A proxy must pass packets with unknown DNS flags, record types, classes, or uncompressed labels instead of rejecting them. The research record locates this support at Sections 4.1 (Unexpected Flags and Data), 4.2 (Label Compression), and 4.3 (Unknown Resource Record Types).
• A proxy should not truncate UDP replies merely because they exceed 512 octets; if it must truncate, it must set TC and must not clear an existing TC bit. The research record locates this support at Section 4.4 (Packet Size Limits).

Keep the evidence boundary at these traced claims. They support a review of authoritative zones, delegations, resolvers, caches, record owners, and the clients that consume the resulting answers; they do not support conclusions outside the source’s stated conditions.

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 Section 3 (The Transparency Principle), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Sections 4.1 (Unexpected Flags and Data), 4.2 (Label Compression), and 4.3 (Unknown Resource Record Types), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 4.4 (Packet Size Limits), 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. Anchor the review in the cited section and keep observation separate from interpretation. 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

Keep the source locations Section 3 (The Transparency Principle); Sections 4.1 (Unexpected Flags and Data), 4.2 (Label Compression), and 4.3 (Unknown Resource Record Types); Section 4.4 (Packet Size Limits) adjacent to the sanitized artifacts used for comparison. Prefer zone data, packet captures, query transcripts, delegation checks, resolver configuration, and negative-answer behavior, with enough identity and timing data for an independent recheck.

Record the decision even when no change is made, including uncertainty and the next trigger. Use safe testing conditions for disruptive work, preserve rollback proof, and revisit the conclusion after relevant platform, dependency, vendor, or ownership changes.

Official references

• RFC 5625 — DNS Proxy Implementation Guidelines — RFC Editor / Internet Engineering Task Force