DMARC
Internet Engineering Task Force (IETF) S. Jones (ed)
Internet-Draft Jones, Ed.
Request for Comments: 9991 DMARC.org
Obsoletes: 7489 (if approved) A. Vesely (ed) Vesely, Ed.
Updates: 6591 (if approved) Tana
Intended status:
Category: Standards Track 18 April 2026
Expires: 20 October May 2026
Domain-based
ISSN: 2070-1721
Domain-Based Message Authentication, Reporting, and Conformance (DMARC)
Failure Reporting
draft-ietf-dmarc-failure-reporting-25
Abstract
Domain-based Message Authentication, Reporting, and Conformance
(DMARC) is a mechanism by which a Domain Owner can request feedback
about email messages using their domain in the From: address field.
This document describes "failure reports", or "failed message
reports", which provide details about individual messages that failed
to authenticate according to the DMARC mechanism.
This document updates RFC 6591 and obsoletes RFC 7489.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of six months this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 20 October 2026.
https://www.rfc-editor.org/info/rfc9991.
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Document Status . . . . . . . . . . . . . . . . . . . . . 4
2. DMARC Failure Reports . . . . . . . . . . . . . . . . . . . . 4
3. Other Failure Reports . . . . . . . . . . . . . . . . . . . . 5
4. Reporting Format Update . . . . . . . . . . . . . . . . . . . 5
5. Verifying External Destinations . . . . . . . . . . . . . . . 6
5.1. Transport . . . . . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6.1. Feedback Report Header Fields Registry Update . . . . . . 7
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 7
7.1. Data Exposure Considerations . . . . . . . . . . . . . . 8
7.2. Report Recipients . . . . . . . . . . . . . . . . . . . . 8
7.3. Additional Damage . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8.1. Denial of Service . . . . . . . . . . . . . . . . . . . . 10
9. References
9.1. Normative References . . . . . . . . . . . . . . . . . . . . 10
10.
9.2. Informative References . . . . . . . . . . . . . . . . . . . 11
Appendix A. Example Failure Report . . . . . . . . . . . . . . . 11
Appendix B. Change Log {change-log} . . . . . . . . . . . . . . 15
B.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 15
B.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 16
B.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 16
B.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 16
B.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 16
B.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 16
B.7. 06 to 07 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.8. 07 to 08 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.9. 08 to 09 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.10. 09 to 10 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.11. 10 to 11 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.12. 11 to 12 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.13. 12 to 13 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.14. 13 to 14 . . . . . . . . . . . . . . . . . . . . . . . . 17
B.15. 14 to 15 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.16. 15 to 16 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.17. 16 to 17 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.18. 17 to 18 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.19. 18 to 19 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.20. 19 to 20 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.21. 20 to 21 . . . . . . . . . . . . . . . . . . . . . . . . 18
B.22. 21 to 22 . . . . . . . . . . . . . . . . . . . . . . . . 19
B.23. 22 to 23 . . . . . . . . . . . . . . . . . . . . . . . . 19
B.24. 23 to 24 . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH BEFORE PUBLISHING:
The source for this draft is maintained in GitHub at:
https://github.com/ietf-wg-dmarc/draft-ietf-dmarc-failure-reporting
(https://github.com/ietf-wg-dmarc/draft-ietf-dmarc-failure-reporting)
Domain-based Message Authentication, Reporting, and Conformance
(DMARC) [I-D.ietf-dmarc-dmarcbis] [RFC9989] is a mechanism by which a mail-
originating mail-originating
organization can express domain-level policies and preferences for
message validation, disposition, and reporting, reporting that can be used by a
mail-receiving organization to improve mail handling. This document
focuses on one type of reporting that can be requested under DMARC.
Failure reports provide detailed information about the failure of a
single message, message or a group of similar messages failing for the same
reason. Their purpose is twofold. On the one hand hand, they are meant
to aid in cases where a Domain Owner wishes to determine the cause of
failures that were part of aggregate reports (see
[I-D.ietf-dmarc-aggregate-reporting]). [RFC9990]). On the
other hand, they can allow the Domain Owner to quickly identify and
address harmful messages involving direct domain abuse. It is
important to note that these reports can contain the header fields or
sometimes the entire content of a failed message, which may contain
personally identifiable information (PII). The potential disclosure
of PII should be considered when deciding whether to request failure
reports as a Domain Owner, or what information to include or redact
in failure reports when creating them as a Mail Receiver, or whether
to create failure reports at all. Refer to Section 7 for more
discussion on privacy considerations.
1.1. Terminology
There are a number of terms defined in Section 3.2 of
[I-D.ietf-dmarc-dmarcbis] [RFC9989] that
are used within this document. Understanding those definitions will
aid in reading this document.
The format of DMARC failure reports is derived from Authentication "Authentication
Failure Reporting Using the Abuse Reporting Format ([RFC6591]) Format" [RFC6591], and
the terms defined there are used here.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Document Status
This document, in part, along with DMARCbis [I-D.ietf-dmarc-dmarcbis]
DMARCbis Aggregate Reporting [I-D.ietf-dmarc-aggregate-reporting], [RFC9989] and [RFC9990], obsoletes
and replaces [RFC7489].
2. DMARC Failure Reports
Besides the header fields or the entire contents of a failed message,
failure reports supply details about transmission and DMARC
authentication, which may aid a Domain Owner in determining the cause
of an authentication failure.
Failure reports are normally generated and sent almost immediately
after the Mail Receiver detects a DMARC failure. Rather than waiting
for an aggregate report, these reports are useful for quickly
notifying the Domain Owners when there is an authentication failure.
Failure reports also provide more information about the failed
message than is available in an aggregate report. This allows the
failure report consumer to better determine whether the failure is of
a message that the domain owner Domain Owner intended to authenticate or one for
which use of its domain was not authorized.
These reports should include as much of the message header fields and
body as possible, consistent with the reporting party's privacy
policies, to enable the Domain Owner to diagnose the authentication
failure.
When a Domain Owner requests failure reports for the purpose of
forensic analysis, and the Mail Receiver is willing to provide such
reports, the Mail Receiver generates and sends a message using the
format described in [RFC6591]; this document updates that reporting
format, as described in Section 4.
The destination(s) to which failure reports are sent, and options for
when they will be sent, are defined by the "ruf" and "fo" tags as
provided in Section 4.7 of [I-D.ietf-dmarc-dmarcbis]. [RFC9989].
When multiple URIs are provided to receive failure reports, the
report generator MUST make an attempt to deliver to each of them.
External destinations MUST be verified, see verified (see Section 5. 5). Report
generators MUST NOT consider "ruf" tags in DMARC Policy Records
having that
have a "psd=y" tag, unless there are specific agreements between the
interested parties.
Report generators MUST implement a rate-limit on outgoing reports so
as not to flood report consumers Report Consumers with excessive reports, which would
allow denial-of-service; see denial of service (see Section 8.1. 8.1).
3. Other Failure Reports
This document describes only describes DMARC failure reports. DKIM DomainKeys
Identified Mail (DKIM) failure reports and SPF Sender Policy Framework
(SPF) failure reports are described in [RFC6591]. A Mail Receiver
generating DMARC failure reports MAY issue failure reports specific
to the failed authentication mechanism instead of, or in addition to,
DMARC failure reports, based on its own policy, the failure in
question, and the content of the "fo" tag in the retrieved DMARC
Policy Record.
Note that DKIM failure reports and SPF failure reports can also be
requested using the methods described in [RFC6651] and [RFC6652],
respectively. Report Generators generators are free to follow any of the
specifications.
4. Reporting Format Update
Operators implementing this specification also implement an augmented
version of failure reporting described in [RFC6591] as follows:
1. A DMARC failure report includes the following ARF Abuse Reporting
Format (ARF) header fields, with the indicated normative
requirement levels:
* Identity-Alignment (REQUIRED; defined below)
* Delivery-Result (OPTIONAL)
* DKIM-Domain, DKIM-Identity, DKIM-Selector (REQUIRED for DKIM
failures of an aligned identifier)
* DKIM-Canonicalized-Header, DKIM-Canonicalized-Body (OPTIONAL
if reporting a DKIM failure)
* SPF-DNS (REQUIRED for SPF failure of an aligned identifier)
2. The "Identity-Alignment" Identity-Alignment field is defined to contain a comma-
separated list of authentication mechanism names that failed to
authenticate an aligned identity, identity or the keyword "none" if all of
the attempted methods were successful at authenticating an
aligned identity. Here is the ABNF ([RFC5234], importing CFWS [RFC5234] (importing comments
and/or folding white space (CFWS) from [RFC5322]):
id-align = "Identity-Alignment:" [CFWS]
( "none" /
dmarc-method *( [CFWS] "," [CFWS] dmarc-method ) )
[CFWS]
dmarc-method = ( "dkim" / "spf" )
; each may appear at most once in an id-align
3. Authentication Failure Type "dmarc" is defined for the Auth-
Failure field, which is to be used when a failure report is
generated because some or all of the authentication mechanisms
failed to produce aligned identifiers. Note that a failure
report generator MAY also independently produce an ARF message
for any or all of the underlying authentication methods.
5. Verifying External Destinations
It is possible to specify destinations for failure reports that are
outside of the Organizational Domain of the DMARC Policy Record that
was requesting the reports. These destinations are commonly referred
to as "external destinations" and may represent a different domain
controlled by the same organization, a contracted report processing
service, or some other arrangement.
In case of external destinations, a Mail Receiver who generates
failure reports MUST use the Verifying External Destinations
procedure described in Section 4 of
[I-D.ietf-dmarc-aggregate-reporting], [RFC9990], substituting the "ruf"
tag where the "rua" tag appears in that procedure.
This prevents a bad actor from publishing a DMARC Policy Record
requesting failure reports to an external destination, destination and then
deliberately sending messages that will generate failure reports as a
form of abuse. It also prevents a Domain Owner from unilaterally
publishing a DMARC Policy Record with an external destination for
failure reports, forcing the external destination to deal with
unwanted messages and potential privacy issues.
5.1. Transport
Email streams carrying DMARC failure reports SHOULD be DMARC-aligned.
We recommend that reporters set a reasonable rate-limit for the
number of failure reports sent to any recipient to avoid overloading
recipient systems. Unaligned reports may in turn produce subsequent
failure reports that could cause mail loops.
6. IANA Considerations
6.1. Feedback Report Header Fields Registry Update
IANA is requested to change has updated the reference and description for the "Identity-Alignment" "Identity-
Alignment" entry in the "Feedback Report Header Fields" registry, which is part of registry
within the "Messaging Abuse Reporting Format (MARF) Parameters"
registry group, as follows:
* "Reference" should change to this document
* "Description" should change to "a
Field Name: Identity-Alignment
Description: a list of authentication mechanism names that failed to
authenticate an aligned identity, or 'none' "none" if all were successful". successful
Multiple Appearances: No
Related "Feedback-Type": auth-failure
Reference: RFC 9991
Status: current
7. Privacy Considerations
The generation and transmission of DMARC failure reports raise
significant privacy concerns that must be carefully considered before
deployment.
Given these factors, many large-scale providers limit or entirely
disable the generation of failure reports, preferring to rely on
aggregate reports, which provide statistical visibility without
exposing sensitive content. Operators that choose to enable failure
reporting are strongly encouraged to:
* Limit the scope and duration of use to targeted diagnostic
activities.
activities;
* Ensure that reporting URIs are carefully controlled and validated. validated;
* Apply minimization techniques, such as redaction of message bodies
and header fields, to reduce sensitive data exposure. exposure;
* Always transmit reports over secure channels.
In summary, while DMARC failure reports can offer diagnostic value,
the associated privacy concerns have led many operators to restrict
their use. Aggregate reports remain the recommended mechanism for
gaining visibility into authentication results while preserving the
confidentiality of end-user communications.
Particular privacy-specific issues are explored below.
7.1. Data Exposure Considerations
Failure reports may include PII and non-public information (NPI) from
messages that fail to authenticate, since these reports may contain
message content as well as trace header fields. These reports may
expose sender and recipient identifiers (e.g., RFC5322.From
addresses), and although the [RFC5965] format used for failed-message
reporting supports redaction ([RFC6590]), [RFC6590], failed-message reporting is
capable of exposing the entire message to the Report Consumer. They
may also expose PII, sensitive business data, or other confidential
communications to unintended recipients. Such exposure can create
regulatory, legal, and operational risks for both senders and
receivers. Examples include product launches, termination notices
for employees, or calendar data. Even innocuous-seeming failures
(such as malformed or "broken" calendar invitations) can result in
the leakage of private communications.
Domain Owners requesting reports will receive information about mail
using their domain, but which they did not actually cause to be sent.
This might provide valuable insight into content used in abusive
messages, but it might also expose PII or NPI from legitimate
messages mistakenly or accidentally failing authentication.
Information about the final destination of mail, where it might
otherwise be obscured by intermediate systems, may be exposed through
a failure report. A commonly cited example is exposure of members of
mailing lists when one list member sends messages to the list, and
failure reports are generated when that message is delivered to other
list members. Those failure reports would be sent to the Domain
Owner of the list member posting the message, message or their delegated
Report Consumer(s).
Similarly, when message forwarding arrangements exist, Domain Owners
requesting reports may receive information about mail forwarded to
domains that were not originally part of their messages' recipient
list. This means that destinations previously unknown to the Domain
Owner may now become visible.
7.2. Report Recipients
A DMARC Policy Record can specify that reports should be sent to a
Report Consumer operating on behalf of the Domain Owner. This might
be done when the Domain Owner sends reports to an entity to monitor
mail streams for deliverability, performance issues, or abuse.
Receipt of such data by third parties may or may not be permitted by
the Mail Receiver's privacy policy, terms of use, et cetera. etc. Domain Owners
and Mail Receivers should both review and understand whether their
own internal policies constrain the use and transmission of DMARC
reporting.
Some potential exists for Report Consumers to perform traffic
analysis, making it possible to obtain metadata about the Mail
Receiver's traffic. In addition to verifying compliance with
policies, Mail Receivers need to consider that before sending reports
to a third party. On the other hand, a Domain Owner may publish a
destination address that appears to be an Internal Report Consumer
but is actually a forwarding address; in this case, the final
destination of a report is not guaranteed.
7.3. Additional Damage
The risks associated with failure reports are compounded by volume
and content distribution concerns. Partially or unredacted reports
may propagate large amounts of spam, phishing, or malware content,
all of which may require special handling by Report Consumers or
other recipients to avoid incidents. This underscores the need to
avoid misconfiguration of the destinations in the "ruf" reporting
URIs,
URIs and the suggestions for redaction in this document, for example example,
using the method described in [RFC6590]. All of these concerns are
heightened for high-volume domains. To mitigate such concerns, the
following steps should be considered:
By report generators:
* Help prevent accidental access to potentially-malicious potentially malicious URIs by
substituting hxxp for http;
* remove Remove attachments which that could embed malicious payload.
By report consumers:
* isolate Isolate report streams from other mail streams;
* use Use sandboxes in evaluating failure reports;
* use Use network segmentation;
* limit Limit access to failure reports to authorized individuals with
appropriate security training.
8. Security Considerations
While reviewing this document and its Security Considerations, security considerations, the
reader should also review the Privacy Considerations privacy considerations above, as well
as the Privacy Considerations privacy considerations and Security Considerations security considerations in sections Sections
10 and 11 of [I-D.ietf-dmarc-dmarcbis]; [RFC9989] and in sections Sections 7 and 8 of
[I-D.ietf-dmarc-aggregate-reporting]. [RFC9990].
8.1. Denial of Service
Failure reports represent a possible denial-of-service attack that
could be perpetrated by an attacker who sends numerous messages
purporting to be from the intended victim Domain Owner but which fail
both SPF and DKIM; this would cause participating Mail Receivers to
send failure reports to the Domain Owner or its delegate(s),
potentially in large numbers. Accordingly, participating Mail
Receivers are encouraged to aggregate these reports as much as is
practical, using the Incidents field of the Abuse Reporting Format ARF [RFC5965]. Indeed,
the aim is not to count each and every failure, failure but rather to report
different failure conditions. Various pruning techniques are
possible, including the following:
* store Store reports for a period of time before sending them, allowing
detection, collection, and consolidation of like incidents;
* apply rate limiting, Apply rate-limiting, such as a maximum number of reports per
minute that will be generated (and the remainder discarded.) discarded).
9. References
9.1. Normative References
[I-D.ietf-dmarc-aggregate-reporting]
Brotman, A., "Domain-based Message Authentication,
Reporting, and Conformance (DMARC) Aggregate Reporting",
Work in Progress, Internet-Draft, draft-ietf-dmarc-
aggregate-reporting-32, 17 March 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-dmarc-
aggregate-reporting-32>.
[I-D.ietf-dmarc-dmarcbis]
Herr, T. and J. R. Levine, "Domain-based Message
Authentication, Reporting, and Conformance (DMARC)", Work
in Progress, Internet-Draft, draft-ietf-dmarc-dmarcbis-41,
4 April 2025, <https://datatracker.ietf.org/doc/html/
draft-ietf-dmarc-dmarcbis-41>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5965] Shafranovich, Y., Levine, J., and M. Kucherawy, "An
Extensible Format for Email Feedback Reports", RFC 5965,
DOI 10.17487/RFC5965, August 2010,
<https://www.rfc-editor.org/info/rfc5965>.
[RFC6590] Falk, J., Ed. and M. Kucherawy, Ed., "Redaction of
Potentially Sensitive Data from Mail Abuse Reports",
RFC 6590, DOI 10.17487/RFC6590, April 2012,
<https://www.rfc-editor.org/info/rfc6590>.
[RFC6591] Fontana, H., "Authentication Failure Reporting Using the
Abuse Reporting Format", RFC 6591, DOI 10.17487/RFC6591,
April 2012, <https://www.rfc-editor.org/info/rfc6591>.
[RFC6692] Clayton, R. and M. Kucherawy, "Source Ports in Abuse
Reporting Format (ARF) Reports", RFC 6692,
DOI 10.17487/RFC6692, July 2012,
<https://www.rfc-editor.org/info/rfc6692>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
10.
[RFC9989] Herr, T., Ed. and J. R. Levine, Ed., "Domain-Based Message
Authentication, Reporting, and Conformance (DMARC)",
RFC 9989, DOI 10.17487/RFC9989, May 2026,
<https://www.rfc-editor.org/info/rfc9989>.
[RFC9990] Brotman, A., Ed., "Domain-Based Message Authentication,
Reporting, and Conformance (DMARC) Aggregate Reporting",
RFC 9990, DOI 10.17487/RFC9990, May 2026,
<https://www.rfc-editor.org/info/rfc9990>.
9.2. Informative References
[RFC6651] Kucherawy, M., "Extensions to DomainKeys Identified Mail
(DKIM) for Failure Reporting", RFC 6651,
DOI 10.17487/RFC6651, June 2012,
<https://www.rfc-editor.org/info/rfc6651>.
[RFC6652] Kitterman, S., "Sender Policy Framework (SPF)
Authentication Failure Reporting Using the Abuse Reporting
Format", RFC 6652, DOI 10.17487/RFC6652, June 2012,
<https://www.rfc-editor.org/info/rfc6652>.
[RFC7489] Kucherawy, M., Ed. and E. Zwicky, Ed., "Domain-based
Message Authentication, Reporting, and Conformance
(DMARC)", RFC 7489, DOI 10.17487/RFC7489, March 2015,
<https://www.rfc-editor.org/info/rfc7489>.
Appendix A. Example Failure Report
This is the full content of a sample failure message, including the
message header.
Received: from gen.example (gen.example [192.0.2.1])
(TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384)
by mail.consumer.example with ESMTPS
id 00000000005DC0DD.0000442E; Tue, 19 Jul 2022 07:57:50 +0200
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;
d=gen.example; s=mail; t=1658210268;
bh=rCrh1aFDE8d/Fltt8wbcu48bLOu4OM23QXqphUZPAIM=;
h=From:To:Date:Subject:From;
b=IND9JkuwF9/5841kzxMbPeej0VYimVzNKozR2R89M8eYO2zOlCBblx507Gz0YK7mE
/h6pslWm0ODBVFzLlwY9CXv4Vu62QsN0RBIXHPjEXOkoM2VCD5zCd+5i5dtCFX7Mxh
LThb2ZJ3efklbSB9RQRwxcmRvCPV7z6lt/Ds9sucVE1RDODYHjx+iWnAUQrlos6ZQb
u/YOUGjf60LPpyljfPu3EpFwo80mSHyQlP/4S5KEykgPQMgCqLPPKvJwu1aAIDj+jG
q2ylO3fmc/ERDeDWACtR67YNabEKBWtjqCRLNxKttazViJTZ5drcLfpX0853KoougX
Rltp7zdoLdy4A==
From: DMARC Filter <DMARC@gen.example>;
To: dmarcfail@consumer.example
Date: Tue, 19 Jul 2022 00:57:48 -0500 (CDT)
Subject: FW: This is the original subject
Mime-Version: 1.0
Content-Type: multipart/report; report-type=feedback-report;
boundary="=_mime_boundary_"
Message-Id: <20220719055748.4AE9D403CC@gen.example>;
This is a MIME-formatted message. If you see this text it means that
your E-mail software does not support MIME-formatted messages.
--=_mime_boundary_
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 7bit
This is an authentication failure report for an email message
received from IP 192.0.2.2 on Tue, 19 Jul 2022 00:57:48 -0500.
--=_mime_boundary_
Content-Type: message/feedback-report
Content-Transfer-Encoding: 7bit
Feedback-Type: auth-failure
Version: 1
User-Agent: DMARC-Filter/1.2.3
Auth-Failure: dmarc
Authentication-Results: gen.example;
dmarc=fail header.from=consumer.example
Identity-Alignment: dkim
DKIM-Domain: consumer.example
DKIM-Identity: @consumer.example
DKIM-Selector: epsilon
Original-Envelope-Id: 65E1A3F0A0
Original-Mail-From: author=gen.example@forwarder.example
Source-IP: 192.0.2.2
Source-Port: 12345
Reported-Domain: consumer.example
--=_mime_boundary_
Content-Type: message/rfc822; charset=utf-8
Content-Transfer-Encoding: 7bit
Authentication-Results: gen.example;
dkim=permerror header.d=forwarder.example header.b="EjCbN/c3";
dkim=temperror header.d=forwarder.example header.b="mQ8GEWPc";
dkim=permerror header.d=consumer.example header.b="hETrymCb";
dkim=neutral header.d=consumer.example header.b="C2nsAp3A";
Received: from mail.forwarder.example
(mail.forwarder.example [IPv6:2001:db8::23ac])
by mail.gen.example (Postfix) with ESMTP id 5E8B0C159826
for <x@gen.example>; Sun, 14 Aug 2022 07:58:29 -0700 (PDT)
Received: from mail.forwarder.example (localhost [127.0.0.1])
by mail.forwarder.example (Postfix) with ESMTP id 4Ln7Qw4fnvz6Bq
for <x@gen.example>; Tue, 19 Jul 2022 07:57:44 +0200
DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed;
d=forwarder.example; s=ed25519-59hs; t=1658210264;
x=1663210264; bh=KYH/g7ForvDbnyyDLYSjauMYMW6sEIqu75/9w3OIONg=;
h=Message-ID:Date:List-Id:List-Archive:List-Post:List-Help:
List-Subscribe:List-Unsubscribe:List-Owner:MIME-Version:Subject:
To:References:From:In-Reply-To:Content-Type:
Content-Transfer-Encoding:autocrypt:cc:content-transfer-encoding:
content-type:date:from:in-reply-to:message-id:mime-version:
openpgp:references:subject:to;
b=EjCbN/c3bTU4QkZH/zwTbYxBDp0k8kpmWSXh5h1M7T8J4vtRo+hvafJazT3ZRgq+7
+4dzEQwUhl+NOJYXXNUAA==
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=forwarder.example; s=rsa-wgJg; t=1658210264; x=1663210264;
bh=KYH/g7ForvDbnyyDLYSjauMYMW6sEIqu75/9w3OIONg=;
h=Message-ID:Date:List-Id:List-Archive:List-Post:List-Help:
List-Subscribe:List-Unsubscribe:List-Owner:MIME-Version:Subject:
To:References:From:In-Reply-To:Content-Type:
Content-Transfer-Encoding:autocrypt:cc:content-transfer-encoding:
content-type:date:from:in-reply-to:message-id:mime-version:
openpgp:references:subject:to;
b=mQ8GEWPcVpBpeqQ88pcbXpGHBT0J/Rwi8Zd2WZTXWWneQGRCOJLRcbBJpjqnrwtqd
76IqawH86tihz4Z/12J1GBCdNx1gfazsoI3yaqfooRDYg0mSyZHrYhQBmodnPcqZj4
/25L5278sc/UNrYO9az2n7R/skbVZ0bvSo2eEiGU8fcpO8+a5SKNYskhaviAI4eGIB
iRMdEP7gP8dESdnZguNbY5HI32UMDpPPNqajzd/BgcqbveYpRrWCDOhcY47POV7GHM
i/KLHiZXtJsL3/Pr/4TL+HTjdX8EDSsy1K5/JCvJCFsJHnSvkEaJQGLn/2m03eW9r8
9w1bQ90aY+VCQ==
X-Original-To: users@forwarder.example
Received: from mail.consumer.example
(mail.consumer.example [192.0.2.4])
(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
key-exchange ECDHE (P-256) server-signature ECDSA (P-384)
server-digest SHA384)
(Client did not present a certificate)
by mail.forwarder.example (Postfix) with ESMTPS id 4Ln7Qs55xmz4nP
for <users@forwarder.example>;
Tue, 19 Jul 2022 07:57:41 +0200 (CEST)
Authentication-Results: mail.forwarder.example;
arc=none smtp.remote-ip=192.0.2.4
Authentication-Results: mail.forwarder.example;
dkim=pass (512-bit key; secure) header.d=consumer.example
header.i=@consumer.example header.a=ed25519-sha256
header.s=epsilon header.b=hETrymCb;
dkim=pass (1152-bit key; secure) header.d=consumer.example
header.i=@consumer.example header.a=rsa-sha256
header.s=delta header.b=C2nsAp3A
DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed;
d=consumer.example; s=epsilon; t=1658210255;
bh=KYH/g7ForvDbnyyDLYSjauMYMW6sEIqu75/9w3OIONg=;
h=Date:Subject:To:References:From:In-Reply-To;
b=hETrymCbz6T1Dyo5dCG9dk8rPykKLdhJCPFeJ9TiiP/kaoN2afpUYtj+SrI+I83lp
p1F/FfYSGy7zz3Q3OdxBA==
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=consumer.example; s=delta; t=1658210255;
bh=KYH/g7ForvDbnyyDLYSjauMYMW6sEIqu75/9w3OIONg=;
h=Date:To:References:From:In-Reply-To;
b=C2nsAp3AMNX33Nq7nN/StPo921xE3XGF8Ju3iAKdYB3EKhsril0N5IjWGlglJECst
jLNKSo7KWZZ2lkH/dVZ9Rs1GHT2uaKy1sc/xmNIC5rHdhrxammiwpTSo4PsT8disfc
3DVF6Q62n0EsdLFqcw1KY8A9inFqYKY2tqoo+y4zMtItqCYx3xjsj3I0IFLuX
Author: Message Author <author@consumer.example>
Received: from [192.0.2.8] (host-8-2-0-192.isp.example [192.0.2.8])
(AUTH: CRAM-MD5 uXDGrn@SYT0/k, TLS: TLS1.3,128bits,
ECDHE_RSA_AES_128_GCM_SHA256)
by mail.consumer.example with ESMTPSA
id 00000000005DC076.00004417; Tue, 19 Jul 2022 07:57:35 +0200
Message-ID: <2431dc66-b010-c9cc-4f2b-a1f889f8bdb4@consumer.example>
Date: Tue, 19 Jul 2022 07:57:33 +0200
List-Id: <users.forwarder.example>
List-Post: <mailto:users@forwarder.example>
List-Help: <mailto:users+help@forwarder.example>
List-Subscribe: <mailto:users+subscribe@forwarder.example>
List-Unsubscribe: <mailto:users+unsubscribe@forwarder.example>
List-Owner: <mailto:users+owner@forwarder.example>
Precedence: list
MIME-Version: 1.0
Subject: This is the original subject
Content-Language: en-US
To: users@forwarder.example
Authentication-Results: consumer.example; auth=pass (details omitted)
From: Message Author <author@consumer.example>
In-Reply-To: <20220718102753.0f6d9dde.cel@example.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
[ Message body was here ]
--=_mime_boundary_--
The Source-Port field definition is given by [RFC6692] [RFC6692].
In the final MIME entity, the local-parts of To and From addresses
are reported unredacted. Since we know that the local parts are PII,
we can reduce the privacy risk by redacting them. In the example,
the report generator could have replaced "users" with "lRLxexey" and
"author" with "RT47aVey" throughout the entity.
If the body of the message is not included, the last MIME entity
would have "Content-Type: text/rfc822-headers" instead of message/
rfc822.
Appendix B. Change Log {change-log}
[RFC Editor: Please remove this section prior to publication.]
B.1. 00 to 01
* Replace references to RFC7489 with references to I-D.ietf-dmarc-
dmarcbis.
* Replace the 2nd paragraph in the Introduction with the text
proposed by Ned for Ticket #55, which enjoys some consensus:
https://mailarchive.ietf.org/arch/msg/dmarc/
HptVyJ9SgrfxWRbeGwORagPrhCw
(https://mailarchive.ietf.org/arch/msg/dmarc/
HptVyJ9SgrfxWRbeGwORagPrhCw)
* Strike a spurious sentence about criticality of feedback, which
was meant for feedback in general, not failure reports. In fact,
failure reports are not critical to establishing and maintaining
accurate authentication deployments. Still attributable to Ticket
#55.
* Remove the content of section "Verifying External Destinations"
and refer to I-D.ietf-dmarc-aggregate-reporting.
* Remove the content of section "Security Considerations" and refer
to I-D.ietf-dmarc-dmarcbis.
* Slightly tweak the wording of the example in Appendix A.1 so that
it makes sense standing alone.
* Remove the sentence containing "must include any URI(s)", as the
issue arose <eref
target="https://mailarchive.ietf.org/arch/msg/dmarc/
mFk0qiTCy8tzghRvcxus01W_Blw"/>.
* Add paragraph in Security Considerations, noting that note that
Organizational Domains are only an approximation...
* Add a Transport section, mentioning DMARC conformance and failure
report mail loops (Ticket #28).
B.2. 01 to 02
* Add a sentence to make clear that counting failures is not the
aim.
B.3. 02 to 03
* Updated references.
B.4. 03 to 04
* Add an example report.
* Remove the old Acknowledgements section.
* Add a IANA Consideration section
B.5. 04 to 05
* Convert to markdown
* Remove irrelevant material.
B.6. 05 to 06
* A Vesely was incorrectly removed from list of document editors.
Corrected.
* Added Terminology section with recoomended boilerplate re:
RFC2119.
B.7. 06 to 07
* Reduce Terminology section
* minor nits
B.8. 07 to 08
* Specify what detailed information a report contains, in the 1st
paragraph of Section 2
* A couple of typos
B.9. 08 to 09
* Replace < with < and > with > in Appendix B
B.10. 09 to 10
* Add an informative section about other failure reports (DKIM, SPF)
B.11. 10 to 11
* Remove appendix with redundant examples - pull request by Daniel
K.
B.12. 11 to 12
* Reference Terminology in [I-D.ietf-dmarc-dmarcbis]
* Expand the Verifying External Destinations section and reference
[I-D.ietf-dmarc-aggregate-reporting]
B.13. 12 to 13
* Update references to numbered sections of
[I-D.ietf-dmarc-dmarcbis] and [I-D.ietf-dmarc-aggregate-reporting]
* Clarify potential information disclosures when failure reports are
sent
* Minor edits for readability and clarity
B.14. 13 to 14
* In the introduction (last paragraph) mention that the purpose is
twofold, debug and anti-abuse.
* In Section 2 (2nd paragraph) clarify that failure reports allow
better determining the failure reason.
B.15. 14 to 15
* Expanded Privacy Considerations section as discussed on list.
* Add tentative IANA Consideration subsections.
B.16. 15 to 16
* Qualification of RFCs 6651/2 in Section 3.
* Spell "Auth-Failure" at bullet 3 of Section 4.
* Cite RFC 6590 when mentioning redaction.
* s/using the wrong sending path/failing authentication/.
* Remove unnecessary IANA Considerations.
B.17. 16 to 17
* Remove the last paragraph of Secority Considerations.
B.18. 17 to 18
* Reword the first purpose (Intro) and cite aggregate-reporting.
* Forward reference to Privacy Consideration.
* s/fo=/"fo"/, /ruf=/ruf/, /urls/URIs/.
* Specify parent registry in IANA Considerations.
B.19. 18 to 19
* Remove the term "scalable" from Abstract and Introduction.
* s/Sender Domain/Domain Owner/.
* Reference to dmarcbis, section 3.2 on its own line.
* Remove the phrase (sometimes referred to as "forensic reports").
* Note that Domain Owner can use dot-forward to not decalre
consumer.
* Mention we could have encrypted the example.
* Don't mention MX.
B.20. 19 to 20
* Replace "dot-forward" with a periphrasis to downplay final
destination.
B.21. 20 to 21
* Move the last paragraph of Section 2 to Security Considerations.
* Explicitly say we obsolete 7489 and update 6591 in the abstract.
* Reword "Without this check, a bad actor ..." in Section 5.
* Fix IANA request.
* Mention RFC 6591 in Terminology (Section 1.1).
B.22. 21 to 22
* Reword obsoleting sentence in the abstract and move it to
Section 1.2.
B.23. 22 to 23
* Merge Med's pull request
B.24. 23 to 24
* "Defang" issue.
* Avoid using "defined by" twice (Section 2, paragraph 5).
* Fix the normative part of rate-limiting (Section 2, paragraph 6).
* Recommend (non-2119) to rate limit (Section 5.1, paragraph 2).
* Reference RFC 5322 (Section 4, bullet 2). "message/
rfc822".
Authors' Addresses
Steven M M. Jones (editor)
DMARC.org
Email: smj@dmarc.org
Alessandro Vesely (editor)
Tana
Email: vesely@tana.it