Resolve link-local names with mDNS probing, scope, and response rules

Keep this document to one review outcome: Resolve link-local names with mDNS probing, scope, and response rules. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 6762 — Multicast DNS from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• Before claiming a unique link-local record, an mDNS responder sends three probes and treats any live answer with that name as a conflict. The research record locates this support at Section 8.1 (Probing).
• Simultaneous probes compare proposed records, and the lexicographically later record wins the tiebreak. The research record locates this support at Section 8.2 (Simultaneous Probe Tiebreaking).
• A host querying an mDNS link-local destination must accept only responses originating on the local link and silently discard other responses. The research record locates this support at Section 11 (Source Address Check).

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 8.1 (Probing), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 8.2 (Simultaneous Probe Tiebreaking), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 11 (Source Address Check), 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.

For an approved change, define prerequisites, a limited test path, success and stop conditions, monitoring, and rollback. Check Windows DNS roles, Active Directory-integrated data, forwarding paths, time, routing, firewalls, and registrar or registry state in design order. Protect credentials, keys, recovery material, personal data, and sensitive topology in evidence.

Verification and evidence

Keep the source locations Section 8.1 (Probing); Section 8.2 (Simultaneous Probe Tiebreaking); Section 11 (Source Address Check) 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.

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 6762 — Multicast DNS — RFC Editor / Internet Engineering Task Force