Preserve internationalized addresses in delivery and disposition reports

Treat this document as a focused evidence review: Preserve internationalized addresses in delivery and disposition reports. Only the official source and traced locations below supply facts. Confirm applicability before acting.

Source fact:

The official RFC 6533 — Internationalized Delivery Status and Disposition Notifications from RFC Editor / Internet Engineering Task Force supports the following bounded statements:

• The UTF-8 address type has native, unitext, and ASCII-safe xtext forms; native UTF-8 cannot be used through a server that lacks SMTPUTF8. The research record locates this support at Section 3 (UTF-8 Address Type).
• A message/global-delivery-status part uses UTF-8 and should preserve non-ASCII recipient addresses in the native UTF-8 address form. The research record locates this support at Section 4.1 (The message/global-delivery-status Media Type).
• A UTF-8 message disposition notification uses message/global-disposition-notification and converts an encoded ORCPT original recipient back to its UTF-8 address form. The research record locates this support at Section 5 (UTF-8 Message Disposition Notifications).

Do not import neighboring assumptions into the source record. The supported task is a scoped comparison involving sending domains, receiving domains, message agents, headers, authentication results, policy records, and failure handling and the conditions the source actually describes.

What the source does not establish

This RFC evidence supports only the named mail-protocol decision; it does not prove provider support, deliverability, or compliance for a particular flow. The citation is not a substitute for observed state, authorization, compliance evidence, or dependency health. Examine authoritative DNS, certificates, time, gateways, identity stores, reputation services, and third-party mail providers before translating the source into an operational decision.

Applicability questions

• For source statement 1 at Section 3 (UTF-8 Address Type), which observable configuration, record, or test can confirm applicability here?
• For source statement 2 at Section 4.1 (The message/global-delivery-status Media Type), which observable configuration, record, or test can confirm applicability here?
• For source statement 3 at Section 5 (UTF-8 Message Disposition Notifications), which observable configuration, record, or test can confirm applicability here?
• Within sending domains, receiving domains, message agents, headers, authentication results, policy records, and failure handling, which versions, roles, and configuration states define the review population?
• Could authoritative DNS, certificates, time, gateways, identity stores, reputation services, and third-party mail providers 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 sending domains, receiving domains, message agents, headers, authentication results, policy records, and failure handling, observed and expected states, owner, and reason for deviation.

An implementation decision needs an owner, approved window, prechecks, observable outcome, stop authority, and rollback path. Validate authoritative DNS, certificates, time, gateways, identity stores, reputation services, and third-party mail providers before and after the test, and store only sanitized operational evidence.

Verification and evidence

Tie each conclusion back to Section 3 (UTF-8 Address Type); Section 4.1 (The message/global-delivery-status Media Type); Section 5 (UTF-8 Message Disposition Notifications) and to observable material such as sanitized messages, DNS records, SMTP transcripts, authentication results, policy evaluation, and delivery or rejection logs. Preserve provenance and stable identifiers without copying secrets into the evidence set.

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 6533 — Internationalized Delivery Status and Disposition Notifications — RFC Editor / Internet Engineering Task Force