Cap resolver retries that amplify failures into unnecessary query load

Keep this document to one review outcome: Cap resolver retries that amplify failures into unnecessary query load. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 4697 — Observed DNS Resolution Misbehavior from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• An iterative resolver must not ask a parent server for the NS RRset of a zone whose listed servers are all nonresponsive. The research record locates this support at Section 2.1.1 (Recommendation).
• A resolver that caches lame servers must key each entry by zone name, class, and server IP address and suppress queries for a configurable interval. The research record locates this support at Section 2.2.1 (Recommendation), lame-server cache key.
• If every server for a zone is marked lame, the resolver should temporarily ignore that status and retry one or more servers. The research record locates this support at Section 2.2.1 (Recommendation), all-servers-lame exception.

The source support ends with the statements listed above. Use them to examine authoritative zones, delegations, resolvers, caches, record owners, and the clients that consume the resulting answers in the applicable environment, not to imply a wider guarantee.

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. It does not establish a deployment’s current state, authorize a production change, prove compliance, or show that Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state are healthy. Documented options are review inputs, not universal mandates.

Applicability questions

• For source statement 1 at Section 2.1.1 (Recommendation), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 2.2.1 (Recommendation), lame-server cache key, which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 2.2.1 (Recommendation), all-servers-lame exception, 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. Make the source, asset scope, owner, and expected outcome explicit in the review record. 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.

Do not move from citation to production in one step. Pilot the decision where practical, observe agreed signals, retain a reversal point, and verify Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state. Handle credentials, keys, recovery data, and personal information through approved secure channels.

Verification and evidence

A reviewer should be able to retrace the decision from Section 2.1.1 (Recommendation); Section 2.2.1 (Recommendation), lame-server cache key; Section 2.2.1 (Recommendation), all-servers-lame exception through zone data, packet captures, query transcripts, delegation checks, resolver configuration, and negative-answer behavior. Record what was collected, where, when, by whom, and which system or role it represents.

Preserve both successful and failed observations, along with approval and rollback evidence. Avoid uncontrolled production experiments. Assign an expiry or event-driven recheck so the conclusion is not treated as permanent.

Official references

• RFC 4697 — Observed DNS Resolution Misbehavior — RFC Editor / Internet Engineering Task Force