Apply the IDNA bidirectional rule before accepting right-to-left labels

Frame this document as a source-led configuration and assurance check: Apply the IDNA bidirectional rule before accepting right-to-left labels. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 5893 — Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA) from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• An IDNA label passes the Bidi Rule only if all six conditions in the rule are satisfied. The research record locates this support at Section 2 (The Bidi Rule).
• The first character determines direction: R or AL makes an RTL label, while L makes an LTR label. The research record locates this support at Section 2 (The Bidi Rule), condition 1.
• An RTL label cannot contain both European-number and Arabic-number Bidi properties. The research record locates this support at Section 2 (The Bidi Rule), condition 4.

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. 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 (The Bidi Rule), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 2 (The Bidi Rule), condition 1, which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 2 (The Bidi Rule), condition 4, 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 2 (The Bidi Rule); Section 2 (The Bidi Rule), condition 1; Section 2 (The Bidi Rule), condition 4 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 5893 — Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA) — RFC Editor / Internet Engineering Task Force