eml1.6 KB

EML — DSN With a 5.7.1 Policy Rejection

A permanent bounce whose extended status is 5.7.1 — rejected by policy — with Remote-MTA, Original-Recipient and Last-Attempt-Date all present. Suppression lists that key on the 5.x class alone blacklist a perfectly valid address over a sender-side problem.

Email parsing Conversion testing

Preview — first 42 lineseml

From: Mail Delivery Subsystem <MAILER-DAEMON@mx1.meridiansupply.example>
To: Maya Chen <maya@brightside.example>
Subject: Delivery Status Notification (policy rejection) SAMPLE
Date: Mon, 16 Feb 2026 07:49:00 -0800
Message-ID: <p7-dsn-policy@mx1.meridiansupply.example>
Auto-Submitted: auto-replied
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status; boundary="=_p7_dsn_p7-dsn-policy"

--=_p7_dsn_p7-dsn-policy
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit

Your message was rejected by the receiving system's policy, not because the
address is wrong. Retrying will not help.
--=_p7_dsn_p7-dsn-policy
Content-Type: message/delivery-status

Reporting-MTA: dns; mx1.meridiansupply.example
Arrival-Date: Mon, 16 Feb 2026 07:45:12 -0800
DSN-Gateway: dns; mx1.meridiansupply.example

Final-Recipient: rfc822; compliance@brightside.example
Original-Recipient: rfc822; compliance@brightside.example
Action: failed
Status: 5.7.1
Remote-MTA: dns; mx.brightside.example
Last-Attempt-Date: Mon, 16 Feb 2026 07:48:55 -0800
Diagnostic-Code: smtp; 550 5.7.1 SAMPLE - message rejected by DMARC policy p=reject
--=_p7_dsn_p7-dsn-policy
Content-Type: text/rfc822-headers

From: Maya Chen <maya@brightside.example>
To: Sam Rivera <sam@meridiansupply.example>
Subject: Standing order for Q1 (SAMPLE)
Date: Mon, 16 Feb 2026 07:45:00 -0800
Message-ID: <p7-dsn-original@brightside.example>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
--=_p7_dsn_p7-dsn-policy--

Specifications

Wave: p7
Seed: 20260807
Report Type: delivery-status
Status: 5.7.1
Status Class: permanent - security or policy
Has Remote Mta: true
Has Original Recipient: true
Line Endings: CRLF (RFC 5322)

Testing contract

Expected to pass

Scenario: Classify a permanent DSN whose 5.7.1 status means a policy rejection rather than an invalid recipient.
Expected result: The bounce is classified as a policy failure, not a bad address; Remote-MTA and Original-Recipient are both parsed from the recipient block.

What is a .eml file?

An EML file is a single email message stored in the RFC 822 / MIME format — plain-text headers (From, To, Subject, Date, Message-ID) followed by the body, which may be plain text, HTML, or a multipart structure with alternative bodies and file attachments encoded in base64.

How to use this file

Use an example EML to test email header parsing, MIME decoding, HTML-part handling, attachment extraction, and EML-to-other-format conversion.

How to use this file for testing

“EML — DSN With a 5.7.1 Policy Rejection” is a deterministic Novus Examples fixture for Email parsing, Conversion testing. Standards-compliant RFC 822 messages — plain, multipart text+HTML, and with an attachment — plus an MBOX mailbox, for testing header parsing, MIME decoding, attachment extraction, and mailbox splitting.

Documented properties for this file: seed 20260807 · CRLF (RFC 5322). Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.

Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.

Email fixtures use fixed dates, message IDs, and MIME boundaries so runs are reproducible, and every address is fictional. Test header parsing, MIME decoding, attachment extraction, and EML/MBOX conversion against the documented structure.

Code examples

from email import policy
from email.parser import BytesParser

msg = BytesParser(policy=policy.default).parse(open("p7-dsn-policy-rejection.eml", "rb"))
print(msg["subject"], msg["from"])