Use DHCID data to identify competing DHCP ownership claims

Keep this document to one review outcome: Use DHCID data to identify competing DHCP ownership claims. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 4701 — A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR) from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• DHCID record data binds DHCP client-identification material to the requested fully qualified domain name through a SHA-256-based digest. The research record locates this support at Sections 3.5 (RDATA Format) and 5 (Updater Behavior).
• An updater recomputes the client identity for the requested name and compares it with any DHCID records already stored at that name. The research record locates this support at Section 5 (Updater Behavior).
• A nonmatching DHCID means another DHCP client is associated with the name, after which site policy decides whether to rename or continue. The research record locates this support at Section 5 (Updater Behavior), mismatch handling.

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 3.5 (RDATA Format) and 5 (Updater Behavior), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 5 (Updater Behavior), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 5 (Updater Behavior), mismatch handling, 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.

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

Tie each conclusion back to Sections 3.5 (RDATA Format) and 5 (Updater Behavior); Section 5 (Updater Behavior); Section 5 (Updater Behavior), mismatch handling 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.

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 4701 — A DNS Resource Record (RR) for Encoding Dynamic Host Configuration Protocol (DHCP) Information (DHCID RR) — RFC Editor / Internet Engineering Task Force