DMARC A. Brotman (ed)
Internet-Draft Comcast, Inc.
Obsoletes: 7489 (if approved) 3 March 2025
Intended status: Standards Track
Expires: 4 September 2025
Domain-based Message Authentication, Reporting, and Conformance (DMARC)
Aggregate Reporting
draft-ietf-dmarc-aggregate-reporting-30
Abstract
Domain-based Message Authentication, Reporting, and Conformance
(DMARC) allows for Domain Owners to request aggregate reports from
receivers. This report is an XML document, and contains extensible
elements that allow for other types of data to be specified later.
The aggregate reports can be submitted by the receiver to the Domain
Owner's specified destination as declared in the associated DNS
record.
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 of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents 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 4 September 2025.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. DMARC Terminology . . . . . . . . . . . . . . . . . . 3
2. Document Status . . . . . . . . . . . . . . . . . . . . . . . 3
3. DMARC Feedback . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Aggregate Reports . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Description of the content XML file . . . . . . . . . 5
3.1.2. Handling Domains in Reports . . . . . . . . . . . . . 13
3.1.3. DKIM Signatures in Aggregate Reports . . . . . . . . 14
3.1.4. Unique Identifiers in Aggregate Reporting . . . . . . 14
3.1.5. Error element . . . . . . . . . . . . . . . . . . . . 14
3.1.6. Policy Override Reason . . . . . . . . . . . . . . . 15
3.2. Extensions . . . . . . . . . . . . . . . . . . . . . . . 15
3.3. Changes in Policy During Reporting Period . . . . . . . . 15
3.4. Report Request Discovery . . . . . . . . . . . . . . . . 16
3.5. Report Delivery . . . . . . . . . . . . . . . . . . . . . 16
3.5.1. Definition of Report-ID . . . . . . . . . . . . . . . 16
3.5.2. Email . . . . . . . . . . . . . . . . . . . . . . . . 17
3.5.3. Other Methods . . . . . . . . . . . . . . . . . . . . 19
3.5.4. Handling of Duplicates . . . . . . . . . . . . . . . 20
4. Verifying External Destinations . . . . . . . . . . . . . . . 20
5. Extensible Reporting . . . . . . . . . . . . . . . . . . . . 22
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
6.1. Registration request for the DMARC namespace: . . . . . . 24
6.2. Registration request for the DMARC XML schema: . . . . . 24
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 24
7.1. Report Recipients . . . . . . . . . . . . . . . . . . . . 24
7.2. Data Contained Within Reports . . . . . . . . . . . . . . 24
7.3. Feedback Leakage . . . . . . . . . . . . . . . . . . . . 25
8. Security Considerations . . . . . . . . . . . . . . . . . . . 26
8.1. Report Contents as an Attack . . . . . . . . . . . . . . 26
8.2. False Information . . . . . . . . . . . . . . . . . . . . 26
8.3. Disclosure of Filtering Information . . . . . . . . . . . 26
9. Operational Considerations . . . . . . . . . . . . . . . . . 27
9.1. Report Generation . . . . . . . . . . . . . . . . . . . . 27
9.2. Report Evaluation . . . . . . . . . . . . . . . . . . . . 27
9.3. Report Storage . . . . . . . . . . . . . . . . . . . . . 27
10. Normative References . . . . . . . . . . . . . . . . . . . . 27
11. Informative References . . . . . . . . . . . . . . . . . . . 29
Appendix A. DMARC XML Schema . . . . . . . . . . . . . . . . . . 30
Appendix B. Sample Report . . . . . . . . . . . . . . . . . . . 37
Appendix C. Differences from RFC7489 . . . . . . . . . . . . . . 38
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Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction
A key component of DMARC [I-D.ietf-dmarc-dmarcbis] (Domain-based
Message Authentication, Reporting, and Conformance) is the ability
for Domain Owners to request that Mail Receivers provide various
types of reports. These reports allow Domain Owners to have insight
into which IP addresses are sending on their behalf, and some insight
into whether or not the volume may be legitimate.
These reports expose information relating to the DMARC policy, as
well as the outcome of SPF (Sender Policy Framework) [RFC7208] & DKIM
(DomainKeys Identified Mail) [RFC6376] validation.
1.1. Terminology
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.
1.1.1. DMARC Terminology
There are a number of terms defined in [I-D.ietf-dmarc-dmarcbis] that
are used within this document. Understanding those definitions will
aid in reading this document. The terms below are of noted interest:
* Author Domain
* DMARC Policy Record
* Domain Owner
* Mail Receiver
* Organizational Domain
* Report Consumer
2. Document Status
This document, in part, along with DMARCbis [I-D.ietf-dmarc-dmarcbis]
DMARCbis Failure Reporting [I-D.ietf-dmarc-failure-reporting],
obsoletes and replaces DMARC [RFC7489].
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3. DMARC Feedback
Providing Domain Owners with visibility into how Mail Receivers
implement and enforce the DMARC mechanism in the form of feedback is
critical to establishing and maintaining accurate authentication
deployments. When Domain Owners can see what effect their policies
and practices are having, they are better willing and able to use
quarantine and reject policies.
3.1. Aggregate Reports
The DMARC aggregate feedback report is designed to provide Domain
Owners with precise insight into:
* authentication results,
* corrective action that needs to be taken by Domain Owners, and
* the effect of Domain Owner DMARC policy on mail streams processed
by Mail Receivers.
Aggregate DMARC feedback provides visibility into real-world mail
streams that Domain Owners need in order to make informed decisions
regarding the publication of a DMARC policy. When Domain Owners know
what legitimate mail they are sending, what the authentication
results are on that mail, and what forged mail receivers are getting,
they can make better decisions about the policies they need and the
steps they need to take to enable those policies. When Domain Owners
set policies appropriately and understand their effects, Mail
Receivers can act on them confidently.
Visibility comes in the form of daily (or more frequent) Mail
Receiver-originated feedback reports that contain aggregate data on
message streams relevant to the Domain Owner. This information
includes data about messages that passed DMARC authentication as well
as those that did not.
A separate report MUST be generated for each Policy Domain
encountered during the reporting period. See below for further
explanation in "Handling Domains in Reports" Section 3.1.2.
The report may include the following data:
* The DMARC policy discovered and applied, if any
* The selected message disposition
* The identifier evaluated by SPF and the SPF result, if any
* The identifier evaluated by DKIM and the DKIM result, if any
* For both DKIM and SPF, an indication of whether the identifier was
in DMARC alignment (see Section 3.2.10 of
[I-D.ietf-dmarc-dmarcbis])
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* Sending and receiving domains
* The number of successful authentications
* The counts of messages based on all messages received, even if
their delivery is ultimately blocked by other filtering agents.
Each report MUST contain data for only one Policy Domain. A single
report MUST contain data for one policy configuration. If multiple
configurations were observed during a single reporting period, a
reporting entity MAY choose to send multiple reports, otherwise the
reporting entity SHOULD note only the final configuration observed
during the period. See below for further information.
3.1.1. Description of the content XML file
NOTE TO RFC EDITOR: We tried a few various formats for these tables.
If you would like to see those other formats, we can send over those
attempts at your request. Please remove this comment before
publishing.
The format for these reports is defined in the XML Schema Definition
(XSD) in Appendix A. The XSD includes the possible values for some
of the elements below. Most of these values have a definition tied
to [I-D.ietf-dmarc-dmarcbis].
The format is also described in the following sections. Each section
describes a collection of sibling elements in the XML hierarchy.
There are pointers to where in the hierarchy each table fits.
If a document does not match the the specified format, the document
evaluator SHOULD discard the report. The evaluator MAY choose to try
to utilize some of the data, though if the format is in question, so
may be the data. The report evaluator MAY choose to contact the
report generator so that they may be alerted to an issue with the
report format.
The column "#" specifies how many times an element may appear, this
is sometimes referred to as multiplicity. The possible values are:
O: OPTIONAL, zero or one element
R: REQUIRED, exactly one element
*: OPTIONAL, zero or more elements
+: REQUIRED, one or more elements
3.1.1.1. XML root element
DMARC Aggregate Feedback Reports have the root element "feedback"
with its XML namespace set to the DMARC namespace.
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+==============+===+===========================================+
| Element name | # | Content |
+==============+===+===========================================+
| feedback | R | First level elements, see Section 3.1.1.2 |
+--------------+---+-------------------------------------------+
Table 1: The XML root element.
3.1.1.2. First Level Elements
The elements in this table MUST appear in the order listed.
+==================+===+============================================+
| Element name | # | Content |
+==================+===+============================================+
| version | O | MUST have the value 1.0. |
+------------------+---+--------------------------------------------+
| report_metadata | R | Report generator metadata, see |
| | | Section 3.1.1.3. |
+------------------+---+--------------------------------------------+
| policy_published | R | The DMARC policy configuration |
| | | observed by the receiving |
| | | system, see Section 3.1.1.5. |
+------------------+---+--------------------------------------------+
| extension | O | Allows for future |
| | | extensibility, see |
| | | Section 3.1.1.6 |
+------------------+---+--------------------------------------------+
| record | + | Record(s) of the feedback from |
| | | the report generator, see |
| | | Section 3.1.1.7. |
+------------------+---+--------------------------------------------+
Table 2: First level elements of the Aggregate Feedback Report.
There MUST be at least one "record" element, they contain data
stating which IP addresses were seen to have delivered messages for
the Author Domain to the receiving system. For each IP address that
is being reported, there will be at least one "record" element.
3.1.1.3. Report generator metadata
+====================+===+=========================================+
| Element name | # | Content |
+====================+===+=========================================+
| org_name | R | Name of the Reporting Organization. |
+--------------------+---+-----------------------------------------+
| email | R | Contact to use when contacting the |
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| | | Reporting Organization. |
+--------------------+---+-----------------------------------------+
| extra_contact_info | O | Additional contact details. |
+--------------------+---+-----------------------------------------+
| report_id | R | Unique Report-ID, see Section 3.5.1. |
+--------------------+---+-----------------------------------------+
| date_range | R | The reporting period, see |
| | | Section 3.1.1.4. |
+--------------------+---+-----------------------------------------+
| error | O | Error messages encountered when |
| | | processing the DMARC Policy Record, see |
| | | Section 3.1.5. |
+--------------------+---+-----------------------------------------+
| generator | O | The name and version of the report |
| | | generator; this can help the Report |
| | | Consumer find out where to report bugs. |
+--------------------+---+-----------------------------------------+
Table 3: Report generator metadata
3.1.1.4. Contents of the "date_range" element
The time range in UTC defining the reporting period of this report.
+==============+===+================================+
| Element name | # | Content |
+==============+===+================================+
| begin | R | Start of the reporting period. |
+--------------+---+--------------------------------+
| end | R | End of the reporting period. |
+--------------+---+--------------------------------+
Table 4: Contents of the "date_range" element
* "begin" and "end" contain the number of seconds since epoch.
The "begin" and "end" are meant to denote the reporting period, and
not the first/last observed message from the reporting period. When
generating reports, these reporting periods SHOULD NOT overlap.
Typically, the reporting period will encompass a single UTC day,
beginning at 0000UTC.
3.1.1.5. Contents of the "policy_published" element
Information on the DMARC Policy Record published for the Author
Domain. The elements from "p" and onwards contain the discovered or
default value for the DMARC policy applied.
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Unspecified tags have their default values.
+==================+===+=======================================+
| Element name | # | Content |
+==================+===+=======================================+
| domain | R | The DMARC Policy Domain. |
+------------------+---+---------------------------------------+
| discovery_method | O | The method used to discover the DMARC |
| | | Policy Record used during evaluation. |
+------------------+---+---------------------------------------+
| p | R | A Domain Owner Assessment Policy. |
+------------------+---+---------------------------------------+
| sp | O | A Domain Owner Assessment Policy. |
+------------------+---+---------------------------------------+
| np | O | A Domain Owner Assessment Policy. |
+------------------+---+---------------------------------------+
| fo | O | The value for the failure reporting |
| | | options. |
+------------------+---+---------------------------------------+
| adkim | O | The DKIM Identifier Alignment mode. |
+------------------+---+---------------------------------------+
| aspf | O | The SPF Identifier Alignment mode. |
+------------------+---+---------------------------------------+
| testing | O | The value of the "t" tag. |
+------------------+---+---------------------------------------+
Table 5: Contents of the "policy_published" element
* "discovery_method" can have the value "psl" or "treewalk", where
"psl" is the method from [RFC7489] and "treewalk" is described in
[I-D.ietf-dmarc-dmarcbis].
* Many of the items above (p, sp, etc.) are defined in the
[I-D.ietf-dmarc-dmarcbis] document.
3.1.1.6. Contents of the "extension" element
Use of extensions may cause elements to be added here. These
elements MUST be namespaced.
+==========================+===+==========================+
| Element name | # | Content |
+==========================+===+==========================+
| <any namespaced element> | * | File level elements |
| | | defined by an extension. |
+--------------------------+---+--------------------------+
Table 6: Contents of the "extension" element
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* "<any namespaced element>"
Zero or more elements in the namespace of the related extension
declared in the XML root element.
3.1.1.7. Contents of the "record" element
The report MUST contain record(s) stating which IP addresses were
seen to have delivered messages for the Author Domain to the
receiving system. For each IP address that is being reported, there
will be at least one "record" element.
This element contains all the authentication results that were
evaluated by the receiving system for the given set of messages.
An unlimited number of "record" elements may be specified.
Use of extensions may cause other elements to be added to the end of
the record, such elements MUST be namespaced.
One record per (IP, result, authenitication identifiers) tuples.
The elements in this table MUST appear in the order listed.
+==============+===+============================================+
| Element name | # | Content |
+==============+===+============================================+
| row | R | See Section 3.1.1.8. |
+--------------+---+--------------------------------------------+
| identifiers | R | The data that was used to apply policy for |
| | | the given "row", see Section 3.1.1.10. |
+--------------+---+--------------------------------------------+
| auth_results | R | The data related to authenticating the |
| | | messages associated with this sending IP |
| | | address, see Section 3.1.1.11. |
+--------------+---+--------------------------------------------+
| <any | * | Record level elements defined by an |
| namespaced | | extension. |
| element> | | |
+--------------+---+--------------------------------------------+
Table 7: Contents of the "record" element
* "<any namespaced element>"
Zero or more elements in the namespace of the related extension
declared in the XML root element.
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3.1.1.8. Contents of the "row" element
A "row" element contains the details of the connecting system, and
how many mails were received from it, for the particular combination
of the policy evaluated.
+==================+===+=======================================+
| Element name | # | Content |
+==================+===+=======================================+
| source_ip | R | The connecting IP address. |
| | | IPv4address or IPv6address as defined |
| | | in Section 3.2.2 of [RFC3986] |
+------------------+---+---------------------------------------+
| count | R | Number of messages for which the |
| | | "policy_evaluated" was applied. |
+------------------+---+---------------------------------------+
| policy_evaluated | R | The DMARC disposition applied to |
| | | matching messages, see |
| | | Section 3.1.1.9. |
+------------------+---+---------------------------------------+
Table 8: Contents of the "row" element
3.1.1.9. Contents of the "policy_evaluated" element
The results of applying the DMARC policy. If alignment fails and the
policy applied does not match the Policy Domain's configured policy,
the "reason" element MUST be included.
The elements in this table MUST appear in the order listed.
+==============+===+==========================================+
| Element name | # | Content |
+==============+===+==========================================+
| disposition | R | The result of applying the DMARC policy. |
+--------------+---+------------------------------------------+
| dkim | R | The result of the DKIM DMARC Identifier |
| | | alignment test. |
+--------------+---+------------------------------------------+
| spf | R | The result of the SPF DMARC Identifier |
| | | alignment test. |
+--------------+---+------------------------------------------+
| reason | * | Policy override reason, see |
| | | Section 3.1.1.14. |
+--------------+---+------------------------------------------+
Table 9: Contents of the "policy_evaluated" element
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* "spf" and "dkim" MUST be the evaluated values as they relate to
DMARC, not the values the receiver may have used when overriding
the policy.
* "reason" elements are meant to include any notes the reporter
might want to include as to why the "disposition" policy does not
match the "policy_published", such as a local policy override.
3.1.1.10. Contents of the "identifiers" element
+===============+===+===========================================+
| Element name | # | Content |
+===============+===+===========================================+
| header_from | R | The RFC5322.From domain from the message. |
+---------------+---+-------------------------------------------+
| envelope_from | O | The RFC5321.MailFrom domain that the SPF |
| | | check has been applied to. |
+---------------+---+-------------------------------------------+
| envelope_to | O | The RFC5321.RcptTo domain from the |
| | | message. |
+---------------+---+-------------------------------------------+
Table 10: Contents of the "identifiers" element
* "envelope_from" MAY be existing but empty if the message had a
null reverse-path (see Section 4.5.5 of [RFC5321]).
* "header_from" is defined in [RFC5598], or Section 3.6.2
3.1.1.11. Contents of the "auth_results" element
Contains DKIM and SPF results, uninterpreted with respect to DMARC.
If validation is attempted for any DKIM signature, the results MUST
be included in the report (within reason, see "DKIM Signatures in
Aggregate Reports" (#dkim-signatures) below for handling numerous
signatures).
The elements in this table MUST appear in the order listed.
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+==============+===+=============================+
| Element name | # | Content |
+==============+===+=============================+
| dkim | * | DKIM authentication result, |
| | | see Section 3.1.1.12. |
+--------------+---+-----------------------------+
| spf | O | SPF authentication result, |
| | | see Section 3.1.1.13. |
+--------------+---+-----------------------------+
Table 11: Contents of the "auth_results" element
3.1.1.12. Contents of the "dkim" element
+==============+===+=============================================+
| Element name | # | Content |
+==============+===+=============================================+
| domain | R | The domain that was used during validation |
| | | (the "d=" tag in the signature). |
+--------------+---+---------------------------------------------+
| selector | R | The selector that was used during |
| | | validation (the "s=" tag in the signature). |
+--------------+---+---------------------------------------------+
| result | R | DKIM verification result, see below. |
+--------------+---+---------------------------------------------+
| human_result | O | More descriptive information to the Domain |
| | | Owner relating to evaluation failures. |
+--------------+---+---------------------------------------------+
Table 12: Contents of the "dkim" element
* "result" is a lower-case string where the value is one of the
results defined in Section 2.7.1 of [RFC8601].
3.1.1.13. Contents of the "spf" element
Only the "MAIL FROM" identity (see Section 2.4 of [RFC7208]) is used
in DMARC.
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+==============+===+=============================================+
| Element name | # | Content |
+==============+===+=============================================+
| domain | R | The domain that was used during validation. |
+--------------+---+---------------------------------------------+
| scope | O | The source of the domain used during |
| | | validation. |
+--------------+---+---------------------------------------------+
| result | R | SPF verification result, see below. |
+--------------+---+---------------------------------------------+
| human_result | O | More descriptive information to the Domain |
| | | Owner relating to evaluation failures. |
+--------------+---+---------------------------------------------+
Table 13: Contents of the "spf" element
* The only valid value for the "scope" element is "mfrom".
* "result" is a lower-case string where the value is one of the
results defined in Section 2.7.2 of [RFC8601].
3.1.1.14. Contents of the "reason" element
The policy override reason consists of a pre-defined override type
and free-text comment, see Section 3.1.6
+==============+===+============================================+
| Element name | # | Content |
+==============+===+============================================+
| type | R | The reason the DMARC policy was overridden |
+--------------+---+--------------------------------------------+
| comment | O | Further details, if available. |
+--------------+---+--------------------------------------------+
Table 14: Contents of the "reason" element
3.1.2. Handling Domains in Reports
In the same report, there MUST be a single Policy Domain, though
there could be multiple RFC5322.From Domains. Each RFC5322.From
domain will create its own "record" within the report. Consider the
case where there are three domains with traffic volume to report:
example.com, foo.example.com, and bar.example.com. There will be
explicit DMARC Policy Records for example.com and bar.example.com,
with distinct policies. There is no explicit DMARC Policy Record for
foo.example.com, so it will be reliant on the policy described for
example.com. For a report period, there would now be two reports.
The first will be for bar.example.com, and contain only one "record",
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for bar.example.com. The second report would be for example.com and
contain multiple "record" elements, one for example.com and one for
foo.example.com (and extensibly, other "record" elements for
subdomains which likewise did not have an explicit DMARC Policy
Record).
3.1.3. DKIM Signatures in Aggregate Reports
Within a single message, the possibility exists that there could be
multiple DKIM signatures. When validation of the message occurs,
some signatures may pass, while some may not. As these pertain to
DMARC, and especially to aggregate reporting, reporters may not find
it clear which DKIM signatures they should include in a report.
Signatures, regardless of outcome, could help the report ingester
determine the source of a message. However, there is a preference as
to which signatures are included.
1. A signature that passes DKIM, in strict alignment with the
RFC5322.From domain
2. A signature that passes DKIM, in relaxed alignment with the
RFC5322.From domain
3. Any other DKIM signatures that pass
4. DKIM signatures that do not pass
A report SHOULD contain no more than 100 signatures for a given
"row", in decreasing priority.
3.1.4. Unique Identifiers in Aggregate Reporting
There are a few places where a unique identifier is specified as part
of the body of the report, the subject, and so on. These unique
identifiers should be consistent per each report. Specified below,
the reader will see a "Report-ID" and "unique-id". These are the
fields that MUST be identical when used.
3.1.5. Error element
A few examples of information contained within the "error"
element(s):
* DMARC Policy Record evaluation errors (invalid "rua" or "sp",
etc.)
* Multiple DMARC Policy Records at a given location
Be mindful that the "error" element is an unbounded string, but
should not contain an extremely large body. Provide enough
information to assist the Domain Owner with understanding some issues
with their authentication or DMARC Policy Record.
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3.1.6. Policy Override Reason
The "reason" element, indicating an override of the DMARC policy,
consists of a mandatory "type" element and an optional "comment"
element. The "type" element MUST have one of the pre-defined values
listed below. The "comment" element is an unbounded string for
providing further details.
Possible values for the policy override type:
"local_policy": The Mail Receiver's local policy exempted the message
from being subjected to the Domain Owner's requested policy action.
"mailing_list": Local heuristics determined that the message arrived
via a mailing list, and thus authentication of the original message
was not expected to succeed.
"other": Some policy exception not covered by the other entries in
this list occurred. Additional detail can be found in the "comment"
element.
"policy_test_mode": The message was exempted from application of
policy by the testing mode ("t" tag) in the DMARC Policy Record.
"trusted_forwarder": Message authentication failure was anticipated
by other evidence linking the message to a locally maintained list of
known and trusted forwarders.
3.2. Extensions
The document format supports optional elements for extensions. The
absence or existence of this section SHOULD NOT create an error when
processing reports. This will be covered in a separate section,
Extensible Reporting, Section 5.
3.3. Changes in Policy During Reporting Period
Note that Domain Owners or their agents may change the published
DMARC Policy Record for a domain or subdomain at any time. From a
Mail Receiver's perspective, this will occur during a reporting
period and may be noticed during that period, at the end of that
period when reports are generated, or during a subsequent reporting
period, all depending on the Mail Receiver's implementation. Under
these conditions, it is possible that a Mail Receiver could do any of
the following:
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* generate for such a reporting period a single aggregate report
that includes message dispositions based on the old policy, or a
mix of the two policies, even though the report only contains a
single "policy_published" element;
* generate multiple reports for the same period, one for each
published policy occurring during the reporting period;
Such policy changes are expected to be infrequent for any given
domain, whereas more stringent policy monitoring requirements on the
Mail Receiver would produce a very large burden at Internet scale.
Therefore, it is the responsibility of Report Consumers (i.e.,
vendors) and Domain Owners to be aware of this situation and expect
such mixed reports during the propagation of the new policy to Mail
Receivers.
3.4. Report Request Discovery
A Mail Receiver discovers reporting requests when it looks up a DMARC
Policy Record that corresponds to an RFC5322.From domain on received
mail. The presence of the "rua" tag specifies where to send
feedback.
3.5. Report Delivery
The Mail Receiver, after preparing a report, MUST evaluate the
provided reporting URIs (See [I-D.ietf-dmarc-dmarcbis]) in the order
given. If any of the URIs are malformed, they SHOULD be ignored. An
attempt MUST be made to deliver an aggregate report to every
remaining URI, up to the Receiver's limits on supported URIs.
If delivery is not possible because the services advertised by the
published URIs are not able to accept reports (e.g., the URI refers
to a service that is unreachable), the Mail Receiver MAY cache that
data and try again later, or MAY discard data that could not be sent.
Where the URI specified in a "rua" tag does not specify otherwise, a
Mail Receiver generating a feedback report SHOULD employ a secure
transport mechanism, meaning the report should be delivered over a
channel employing TLS (SMTP+STARTTLS).
3.5.1. Definition of Report-ID
This identifier MUST be unique among reports to the same domain to
aid receivers in identifying duplicate reports should they happen.
The Report-ID value should be constructed using the following ABNF
[RFC5234]:
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ridfmt = (dot-atom-text ["@" dot-atom-text]) ; from RFC5322
ridtxt = ("<" ridfmt ">") / ridfmt
The format specified here is not very strict as the key goal is
uniqueness. In order to create this uniqueness, the Mail Receiver
may wish to use elements such as the receiving domain, sending
domain, and a timestamp in combination. An example string might be
"1721054318-example.com@example.org". An alternate could use a date
string such as "2024-03-27_example.com@example.org".
3.5.2. Email
The message generated by the Mail Receiver MUST be a [RFC5322]
message formatted per [RFC2045]. The aggregate report itself MUST be
included in one of the parts of the message, as an attachment with a
corresponding media type from below. A human-readable annotation MAY
be included as a body part (with a human-friendly content-type, such
as "text/plain" or "text/html").
The aggregate data MUST be an XML file that SHOULD be subjected to
GZIP [RFC1952] compression. Declining to apply compression can cause
the report to be too large for a receiver to process (the total
message size could exceed the receiver SMTP size limit); doing the
compression increases the chances of acceptance of the report at some
compute cost. The aggregate data MUST be present using the media
type "application/gzip" if compressed (see [RFC6713]), and "text/xml"
otherwise. The attachment filename MUST be constructed using the
following ABNF:
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filename = receiver "!" policy-domain "!" begin-timestamp
"!" end-timestamp [ "!" unique-id ] "." extension
receiver = domain
; imported from [@!RFC5322]
policy-domain = domain
begin-timestamp = 1*DIGIT
; seconds since 00:00:00 UTC January 1, 1970
; indicating start of the time range contained
; in the report
end-timestamp = 1*DIGIT
; seconds since 00:00:00 UTC January 1, 1970
; indicating end of the time range contained
; in the report
unique-id = 1*(ALPHA / DIGIT)
extension = "xml" / "xml.gz"
The extension MUST be "xml" for a plain XML file, or "xml.gz" for an
XML file compressed using GZIP.
"unique-id" allows an optional unique ID generated by the Mail
Receiver to distinguish among multiple reports generated
simultaneously by different sources within the same Domain Owner. A
viable option may be to explore UUIDs [RFC9562].
If a report generator needs to re-send a report, the system MUST use
the same filename as the original report. This would allow the
receiver to overwrite the data from the original, or discard second
instance of the report.
For example, this is a sample filename for the gzip file of a report
to the Domain Owner "example.com" from the Mail Receiver
"mail.receiver.example":
mail.receiver.example!example.com!1013662812!1013749130.xml.gz
No specific MIME message structure is required for the message body.
It is presumed that the aggregate reporting address will be equipped
to extract body parts with the prescribed media type and filename and
ignore the rest.
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Mail streams carrying DMARC feedback data MUST conform to the DMARC
mechanism, thereby resulting in an aligned "pass" (see Section 4.4 of
[I-D.ietf-dmarc-dmarcbis]). This practice minimizes the risk of
Report Consumers processing fraudulent reports.
The RFC5322.Subject field for individual report submissions MUST
conform to the following ABNF:
dmarc-subject = %s"Report" 1*FWS %s"Domain:"
1*FWS domain-name 1*FWS ; policy domain
%s"Submitter:" 1*FWS
domain-name 1*FWS ; report generator
[ %s"Report-ID:" 1*FWS ridtxt ] ; defined below
The first domain-name indicates the DNS domain name about which the
report was generated. The second domain-name indicates the DNS
domain name representing the Mail Receiver generating the report.
The purpose of the Report-ID: portion of the field is to enable the
Domain Owner to identify and ignore duplicate reports that might be
sent by a Mail Receiver.
For instance, this is a possible Subject field for a report to the
Domain Owner "example.com" from the Mail Receiver
"mail.receiver.example". It is folded as allowed by [RFC5322]:
Subject: Report Domain: example.com
Submitter: mail.receiver.example
Report-ID: <sample-ridtxt@example.com>
This transport mechanism potentially encounters a problem when
feedback data size exceeds maximum allowable attachment sizes for
either the generator or the consumer.
Optionally, the report sender MAY choose to use the same "ridtxt" as
a part or whole of the RFC5322.Message-Id header included with the
report. Doing so may help receivers distinguish when a message is a
re-transmission or duplicate report.
3.5.3. Other Methods
The specification as written allows for the addition of other
registered URI schemes to be supported in later versions.
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3.5.4. Handling of Duplicates
There may be a situation where the report generator attempts to
deliver duplicate information to the receiver. This may manifest as
an exact duplicate of the report, or as duplicate information between
two reports. In these situations, the decision of how to handle the
duplicate data lies with the receiver. As noted above, the sender
MUST use the same unique identifiers when sending the report. This
allows the receiver to better understand when duplicates happen. A
few options on how to handle that duplicate information:
* Reject back to sender, ideally with a permfail error noting the
duplicate receipt
* Discard upon receipt
* Inspect the contents to evaluate the timestamps and reported data,
act as appropriate
* Accept the duplicate data
When accepting the data, that's likely in a situation where it's not
yet noticed, or a one-off experience. Long term, duplicate data is
not ideal. In the situation of a partial time frame overlap, there
is no clear way to distinguish the impact of the overlap. The
receiver would need to accept or reject the duplicate data in whole.
4. Verifying External Destinations
It is possible to specify destinations for the different reports that
are outside the authority of the Domain Owner making the request.
This allows domains that do not operate mail servers to request
reports and have them go someplace that is able to receive and
process them.
Without checks, this would allow a bad actor to publish a DMARC
Policy Record that requests that reports be sent to a victim address,
and then send a large volume of mail that will fail both DKIM and SPF
checks to a wide variety of destinations; the victim will in turn be
flooded with unwanted reports. Therefore, a verification mechanism
is included.
When a Mail Receiver discovers a DMARC Policy Record in the DNS, and
the Organizational Domain at which that record was discovered is not
identical to the Organizational Domain of the host part of the
authority component of a [RFC3986] specified in the "rua" tag, the
following verification steps MUST be taken:
1. Extract the host portion of the authority component of the URI.
Call this the "destination host", as it refers to a Report
Receiver.
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2. Prepend the string "_report._dmarc".
3. Prepend the domain name from which the policy was retrieved,
after conversion to an A-label [RFC5890] if needed.
4. If the length of the constructed name exceed DNS limits, a
positive determination of the external reporting relationship
cannot be made; stop.
5. Query the DNS for a TXT record at the constructed name. If the
result of this request is a temporary DNS error of some kind
(e.g., a timeout), the Mail Receiver MAY elect to temporarily
fail the delivery so the verification test can be repeated later.
6. For each record returned, parse the result as a series of
"tag=value" pairs, i.e., the same overall format as the policy
record (see Section 4.7 of [I-D.ietf-dmarc-dmarcbis]). In
particular, the "v=DMARC1" tag is mandatory and MUST appear first
in the list. Discard any that do not pass this test. A trailing
";" is optional.
7. If the result includes no TXT resource records that pass basic
parsing, a positive determination of the external reporting
relationship cannot be made; stop.
8. If at least one TXT resource record remains in the set after
parsing, then the external reporting arrangement was authorized
by the Report Consumer.
9. If a "rua" tag is thus discovered, replace the corresponding
value extracted from the domain's DMARC Policy Record with the
one found in this record. This permits the Report Consumer to
override the report destination. However, to prevent loops or
indirect abuse, the overriding URI MUST use the same destination
host from the first step.
For example, if the DMARC Policy Record for "blue.example.com"
contained "rua=mailto:reports@red.example.net", the Organizational
Domain host extracted from the latter ("red.example.net") does not
match "blue.example.com", so this procedure is enacted. A TXT query
for "blue.example.com._report._dmarc.red.example.net" is issued. If
a single reply comes back containing a tag of "v=DMARC1", then the
relationship between the two is confirmed. Moreover,
"red.example.net" has the opportunity to override the report
destination requested by "blue.example.com" if needed.
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Where the above algorithm fails to confirm that the external
reporting was authorized by the Report Consumer, the URI MUST be
ignored by the Mail Receiver generating the report. Further, if the
confirming record includes a URI whose host is again different than
the domain publishing that override, the Mail Receiver generating the
report MUST NOT generate a report to either the original or the
override URI. A Report Consumer publishes such a record in its DNS
if it wishes to receive reports for other domains.
A Report Consumer that is willing to receive reports for any domain
can use a wildcard DNS record. For example, a TXT resource record at
"*._report._dmarc.example.com" containing at least "v=DMARC1"
confirms that example.com is willing to receive DMARC reports for any
domain.
If the Report Consumer is overcome by volume, it can simply remove
the confirming DNS record. However, due to positive caching, the
change could take as long as the time-to-live (TTL) on the record to
go into effect.
If the length of the DNS query is excessively long (Step 4 above),
the Domain Owner may need to reconsider the domain being used to be
shorter, or reach out to another party that may allow for a shorter
DNS label.
5. Extensible Reporting
DMARC reports allow for some extensibility, as defined by future
documents that utilize DMARC as a foundation. These extensions MUST
be properly formatted XML and meant to exist within the structure of
a DMARC report. Two positions of type "<any>" are provided in the
existing DMARC structure, one at file level, in an "<extension>"
element after "<policy_published>" and one at record level, after
"<auth_results>". In either case, the extensions MUST contain a URI
to the definition of the extension so that the receiver understands
how to interpret the data.
At file level:
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<feedback xmlns="urn:ietf:params:xml:ns:dmarc-2.0"
xmlns:ext="URI for an extension-supplied name space">
...
<policy_published>
<domain>example.com</domain>
<p>quarantine</p>
<sp>none</sp>
<testing>n</testing>
</policy_published>
<extension>
<ext:arc-override>never</ext:arc-override>
</extension>
Within the "record" element:
<record>
<row>
...
</row>
<identifiers>
...
</identifiers>
<auth_results>
...
</auth_results>
<ext:arc-results>
...
</ext:arc-results>
</record>
<record>
...
Here "arc-override" and "arc-results" are hypothetical element names
defined in the extension's name space.
Extension elements are optional. Any number of extensions is
allowed. If a processor is unable to handle an extension in a
report, it SHOULD ignore the data and continue to the next extension.
6. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemas
conforming to a registry mechanism described in [RFC3688]. Two URI
assignments will be registered by the IANA.
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6.1. Registration request for the DMARC namespace:
URI: urn:ietf:params:xml:ns:dmarc-2.0
Registrant Contact: Internet Engineering Task Force (iesg@ietf.org)
XML: None. Namespace URIs do not represent an XML specification.
6.2. Registration request for the DMARC XML schema:
URI: urn:ietf:params:xml:schema:dmarc-2.0
Registrant Contact: Internet Engineering Task Force (iesg@ietf.org)
XML: See Appendix A. DMARC XML Schema ([W3C.REC-xmlschema-1] and
[W3C.REC-xmlschema-2]) in this document.
7. Privacy Considerations
This section will discuss exposure related to DMARC aggregate
reporting.
7.1. Report Recipients
A DMARC Policy Record can specify that reports should be sent to an
intermediary operating on behalf of the Domain Owner. This is done
when the Domain Owner contracts with an entity to monitor mail
streams for abuse and performance issues. Receipt by third parties
of such data may or may not be permitted by the Mail Receiver's
privacy policy, terms of use, or other similar governing document.
Domain Owners and Mail Receivers should both review and understand if
their own internal policies constrain the use and transmission of
DMARC reporting.
Some potential exists for report recipients to perform traffic
analysis, making it possible to obtain metadata about the Receiver's
traffic. In addition to verifying compliance with policies,
Receivers need to consider that before sending reports to a third
party.
7.2. Data Contained Within Reports
Aggregate feedback reports contain aggregated data relating to
messages purportedly originating from the Domain Owner. The data
does not contain any identifying characteristics about individual
users. No personal information such as individual mail addresses, IP
addresses of individuals, or the content of any messages, is included
in reports.
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Mail Receivers should have no concerns in sending reports as they do
not contain personal information. In all cases, the data within the
reports relates to the domain-level authentication information
provided by mail servers sending messages on behalf of the Domain
Owner. This information is necessary to assist Domain Owners in
implementing and maintaining DMARC.
Domain Owners should have no concerns in receiving reports as they do
not contain personal information. The reports only contain
aggregated data related to the domain-level authentication details of
messages claiming to originate from their domain. This information
is essential for the proper implementation and operation of DMARC.
Domain Owners who are unable to receive reports for organizational
reasons, can choose to exclusively direct the reports to an external
processor.
7.3. Feedback Leakage
Providing feedback reporting to PSOs (Public Suffix Operator) for a
PSD (Public Suffix Domain) [I-D.ietf-dmarc-dmarcbis] can, in some
cases, cause information to leak out of an organization to the PSO.
This leakage could potentially be utilized as part of a program of
pervasive surveillance (see [RFC7624]). There are roughly three
cases to consider:
* Single Organization PSDs (e.g., ".mil")
Aggregate reports based on PSD DMARC have the potential to contain
information about mails related to entities managed by the
organization. Since both the PSO and the Organizational Domain
Owners are common, there is no additional privacy risk for either
normal or non-existent domain reporting due to PSD DMARC.
* Multi-organization PSDs requiring DMARC usage (e.g., ".bank")
Aggregate reports based on PSD DMARC will only be generated for
domains that do not publish a DMARC Policy Record at the
Organizational Domain or host level. For domains that do publish
the required DMARC Policy Records, the feedback reporting
addresses of the Organizational Domain (or hosts) will be used.
The only direct risk of feedback leakage for these PSDs are for
Organizational Domains that are out of compliance with PSD policy.
Data on non-existent domains would be sent to the PSO.
* Multi-organization PSDs not requiring DMARC usage (e.g., ".com")
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Privacy risks for Organizational Domains that have not deployed
DMARC within such PSDs can be significant. For non-DMARC
Organizational Domains, all DMARC feedback will be directed to the
PSO if that PSO itself has a DMARC Policy Record that specifies a
"rua" tag. Any non-DMARC Organizational Domain would have its
Feedback Reports redirected to the PSO. The content of such
reports, particularly for existing domains, is privacy sensitive.
PSOs will receive feedback on non-existent domains, which may be
similar to existing Organizational Domains. Feedback related to such
domains have a small risk of carrying information related to an
actual Organizational Domain. To minimize this potential concern,
PSD DMARC feedback MUST be limited to Aggregate Reports. Failure
Reports carry more detailed information and present a greater risk.
8. Security Considerations
While reviewing this document and its Security Considerations, it is
ideal that the reader would also review Privacy Considerations above,
as well as the Privacy Considerations and Security Considerations in
section 9 and 10 of [I-D.ietf-dmarc-dmarcbis].
8.1. Report Contents as an Attack
Aggregate reports are supposed to be processed automatically. An
attacker might attempt to compromise the integrity or availability of
the report processor by sending malformed reports. In particular,
the archive decompressor and XML parser are at risk to resource
exhaustion attacks (zip bomb or XML bomb).
8.2. False Information
The data contained within aggregate reports may be forged. An
attacker might attempt to interfere with or influence policy
decisions by submitting false reports in large volume. The attacker
could also be attempting to influence platform architecture
decisions. A volume-based attack may also impact the ability for a
report receiver to accept reports from other entities.
8.3. Disclosure of Filtering Information
While not specified in this document itself, the availability of
extensions could enable the report generator to disclose information
about message placement (Inbox/Spam/etc). This is very much
discouraged as it could relay this information to a malicious party,
allowing them to understand more about filtering methodologies at a
receiving entity.
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9. Operational Considerations
9.1. Report Generation
* The error fields should be reasonably terse and usable.
* If reports cannot be generator, the system should ideally log a
useful error that helps troubleshoot the issue.
9.2. Report Evaluation
As noted above, if a report does not match the specified format, the
evaluator will likely find the contents to be in question.
Alternately, the evaluator may decide to sideline those reports so
they can more easily collaborate with the report generator to
identify where the issues are happening.
It's quite likely that the data contained within the reports will be
extracted and stored in a system that allows for easy reporting,
dashboarding, and/or monitoring. The XML reports themselves are not
human readable in bulk, and a system such as the above may aid the
Domain Owner with identifying issues.
9.3. Report Storage
Once a report is accepted and properly parsed by the report
evaluator, it is entirely up to that evaluator what they wish to do
with the XML documents. For some domains, the quantity of reports
could be fairly high, or the size of the reports themselves could be
large. Once the data from the reports has been extracted and
indexed, the reports seemingly have little value in most situations.
10. 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-28, 10 February 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-dmarc-
aggregate-reporting-28>.
[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-39,
13 February 2025, <https://datatracker.ietf.org/doc/html/
draft-ietf-dmarc-dmarcbis-39>.
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[RFC1952] Deutsch, P., "GZIP file format specification version 4.3",
RFC 1952, DOI 10.17487/RFC1952, May 1996,
<https://www.rfc-editor.org/info/rfc1952>.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<https://www.rfc-editor.org/info/rfc2045>.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[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>.
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<https://www.rfc-editor.org/info/rfc5321>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
RFC 5890, DOI 10.17487/RFC5890, August 2010,
<https://www.rfc-editor.org/info/rfc5890>.
[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>.
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[RFC6713] Levine, J., "The 'application/zlib' and 'application/gzip'
Media Types", RFC 6713, DOI 10.17487/RFC6713, August 2012,
<https://www.rfc-editor.org/info/rfc6713>.
[RFC7208] Kitterman, S., "Sender Policy Framework (SPF) for
Authorizing Use of Domains in Email, Version 1", RFC 7208,
DOI 10.17487/RFC7208, April 2014,
<https://www.rfc-editor.org/info/rfc7208>.
[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>.
[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>.
[RFC8601] Kucherawy, M., "Message Header Field for Indicating
Message Authentication Status", RFC 8601,
DOI 10.17487/RFC8601, May 2019,
<https://www.rfc-editor.org/info/rfc8601>.
[W3C.REC-xmlschema-1]
Thompson, H., Beech, D., Maloney, M., and N. Mendelsohn,
"XML Schema Part 1: Structures", W3C REC-xmlschema-1, 2
May 2001, <http://www.w3.org/TR/xmlschema-1/>.
[W3C.REC-xmlschema-2]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes",
W3C REC-xmlschema-2, 2 May 2001,
<http://www.w3.org/TR/xmlschema-2/>.
11. Informative References
[I-D.ietf-dmarc-failure-reporting]
Jones, S. M. and A. Vesely, "Domain-based Message
Authentication, Reporting, and Conformance (DMARC) Failure
Reporting", Work in Progress, Internet-Draft, draft-ietf-
dmarc-failure-reporting-12, 9 January 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-dmarc-
failure-reporting-12>.
[RFC5598] Crocker, D., "Internet Mail Architecture", RFC 5598,
DOI 10.17487/RFC5598, July 2009,
<https://www.rfc-editor.org/info/rfc5598>.
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[RFC7624] Barnes, R., Schneier, B., Jennings, C., Hardie, T.,
Trammell, B., Huitema, C., and D. Borkmann,
"Confidentiality in the Face of Pervasive Surveillance: A
Threat Model and Problem Statement", RFC 7624,
DOI 10.17487/RFC7624, August 2015,
<https://www.rfc-editor.org/info/rfc7624>.
[RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique
IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May
2024, <https://www.rfc-editor.org/info/rfc9562>.
Appendix A. DMARC XML Schema
<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
targetNamespace="urn:ietf:params:xml:ns:dmarc-2.0"
xmlns="urn:ietf:params:xml:ns:dmarc-2.0"
elementFormDefault="qualified">
<!-- The time range in UTC defining the reporting period of
this report, specified in seconds since epoch. -->
<xs:complexType name="DateRangeType">
<xs:all>
<xs:element name="begin" type="xs:integer"
minOccurs="1" maxOccurs="1"/>
<xs:element name="end" type="xs:integer"
minOccurs="1" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- Report generator metadata. -->
<xs:complexType name="ReportMetadataType">
<xs:all>
<!-- Reporting Organization -->
<xs:element name="org_name" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- Contact to use when contacting the Reporting Organization -->
<xs:element name="email" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- Additional contact details -->
<xs:element name="extra_contact_info" type="xs:string"
minOccurs="0" maxOccurs="1"/>
<!-- Unique Report-ID -->
<xs:element name="report_id" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- Timestamps used when forming report data -->
<xs:element name="date_range" type="DateRangeType"
minOccurs="1" maxOccurs="1"/>
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<!-- Optional error messages when processing DMARC policy -->
<xs:element name="error" type="xs:string"
minOccurs="0" maxOccurs="1"/>
<!-- Optional information about the generating software -->
<xs:element name="generator" type="xs:string"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- Alignment mode (relaxed or strict) for DKIM and SPF. -->
<xs:simpleType name="AlignmentType">
<xs:restriction base="xs:string">
<xs:enumeration value="r"/>
<xs:enumeration value="s"/>
</xs:restriction>
</xs:simpleType>
<!-- The policy actions specified by p, sp and np in the
DMARC Policy Record. -->
<xs:simpleType name="DispositionType">
<xs:restriction base="xs:string">
<xs:enumeration value="none"/>
<xs:enumeration value="quarantine"/>
<xs:enumeration value="reject"/>
</xs:restriction>
</xs:simpleType>
<!-- The policy actions utilized on messages for this record. -->
<!--
"none": No action taken
"pass": No action, passing DMARC w/enforcing policy
"quarantine": Failed DMARC, message marked for quarantine
"reject": Failed DMARC, marked as reject
-->
<xs:simpleType name="ActionDispositionType">
<xs:restriction base="xs:string">
<xs:enumeration value="none"/>
<xs:enumeration value="pass"/>
<xs:enumeration value="quarantine"/>
<xs:enumeration value="reject"/>
</xs:restriction>
</xs:simpleType>
<!-- The method used to discover the DMARC Policy Record used during
evaluation. The available values are "psl" and "treewalk",
where "psl" is the method from [@?RFC7489] and the "treewalk"
is described in [@I-D.ietf-dmarc-dmarcbis]. -->
<xs:simpleType name="DiscoveryType">
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<xs:restriction base="xs:string">
<xs:enumeration value="psl"/>
<xs:enumeration value="treewalk"/>
</xs:restriction>
</xs:simpleType>
<!-- The published DMARC policy. Unspecified tags have their
default values. -->
<xs:complexType name="PolicyPublishedType">
<xs:all>
<!-- The domain at which the DMARC record was found. -->
<xs:element name="domain" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The policy published for messages from: -->
<!-- * the domain. -->
<xs:element name="p" type="DispositionType"
minOccurs="1" maxOccurs="1"/>
<!-- * subdomains. -->
<xs:element name="sp" type="DispositionType"
minOccurs="0" maxOccurs="1"/>
<!-- * non-existent subdomains. -->
<xs:element name="np" type="DispositionType"
minOccurs="0" maxOccurs="1"/>
<!-- The DKIM alignment mode. -->
<xs:element name="adkim" type="AlignmentType"
minOccurs="0" maxOccurs="1"/>
<!-- The SPF alignment mode. -->
<xs:element name="aspf" type="AlignmentType"
minOccurs="0" maxOccurs="1"/>
<!-- Method used to find/obtain DMARC policy -->
<xs:element name="discovery_method" type="DiscoveryType"
minOccurs="0" maxOccurs="1"/>
<!-- Failure reporting options in effect. -->
<xs:element name="fo" type="xs:string"
minOccurs="0" maxOccurs="1"/>
<!-- Whether testing mode was declared in the DMARC Record -->
<xs:element name="testing" type="TestingType"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- Values for Testing mode attached to policy -->
<xs:simpleType name="TestingType">
<xs:restriction base="xs:string">
<xs:enumeration value="n"/>
<xs:enumeration value="y"/>
</xs:restriction>
</xs:simpleType>
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<!-- The DMARC-aligned authentication result. -->
<xs:simpleType name="DMARCResultType">
<xs:restriction base="xs:string">
<xs:enumeration value="pass"/>
<xs:enumeration value="fail"/>
</xs:restriction>
</xs:simpleType>
<!-- Reasons that may affect DMARC disposition or execution. -->
<xs:simpleType name="PolicyOverrideType">
<xs:restriction base="xs:string">
<xs:enumeration value="local_policy"/>
<xs:enumeration value="mailing_list"/>
<xs:enumeration value="other"/>
<xs:enumeration value="policy_test_mode"/>
<xs:enumeration value="trusted_forwarder"/>
</xs:restriction>
</xs:simpleType>
<!-- Override reason consists of pre-defined override type and
free-text comment. -->
<xs:complexType name="PolicyOverrideReason">
<xs:all>
<xs:element name="type" type="PolicyOverrideType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="comment" type="xs:string"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- Taking into account everything else in the record,
the results of applying DMARC. If alignment fails
and the policy applied does not match the domain's
configured policy, the reason element MUST be specified -->
<xs:complexType name="PolicyEvaluatedType">
<xs:sequence>
<xs:element name="disposition" type="ActionDispositionType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="dkim" type="DMARCResultType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="spf" type="DMARCResultType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="reason" type="PolicyOverrideReason"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="RowType">
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<xs:all>
<!-- The connecting IP. IPv4address or IPv6address
as defined in RFC 3986 section 3.2.2 -->
<xs:element name="source_ip" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The number of messages for which the
PolicyEvaluatedType was applied. -->
<xs:element name="count" type="xs:integer"
minOccurs="1" maxOccurs="1"/>
<!-- The DMARC disposition applied to matching messages. -->
<xs:element name="policy_evaluated" type="PolicyEvaluatedType"
minOccurs="1" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<xs:complexType name="IdentifierType">
<xs:all>
<!-- The RFC5322.From domain. -->
<xs:element name="header_from" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The RFC5321.MailFrom domain -->
<xs:element name="envelope_from" type="xs:string"
minOccurs="0" maxOccurs="1"/>
<!-- The envelope recipient domain. -->
<xs:element name="envelope_to" type="xs:string"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- DKIM verification result, see RFC 8601 Section 2.7.1. -->
<xs:simpleType name="DKIMResultType">
<xs:restriction base="xs:string">
<xs:enumeration value="none"/>
<xs:enumeration value="pass"/>
<xs:enumeration value="fail"/>
<xs:enumeration value="policy"/>
<xs:enumeration value="neutral"/>
<xs:enumeration value="temperror"/>
<xs:enumeration value="permerror"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="DKIMAuthResultType">
<xs:all>
<!-- The "d=" tag in the signature. -->
<xs:element name="domain" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The "s=" tag in the signature. -->
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<xs:element name="selector" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The DKIM verification result. -->
<xs:element name="result" type="DKIMResultType"
minOccurs="1" maxOccurs="1"/>
<!-- Any extra information (e.g., from Authentication-Results). -->
<xs:element name="human_result" type="xs:string"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- SPF domain scope. -->
<xs:simpleType name="SPFDomainScope">
<xs:restriction base="xs:string">
<xs:enumeration value="mfrom"/>
</xs:restriction>
</xs:simpleType>
<!-- SPF verification result, see RFC 8601 Section 2.7.2. -->
<xs:simpleType name="SPFResultType">
<xs:restriction base="xs:string">
<xs:enumeration value="none"/>
<xs:enumeration value="pass"/>
<xs:enumeration value="fail"/>
<xs:enumeration value="softfail"/>
<xs:enumeration value="policy"/>
<xs:enumeration value="neutral"/>
<xs:enumeration value="temperror"/>
<xs:enumeration value="permerror"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="SPFAuthResultType">
<xs:all>
<!-- The checked domain. -->
<xs:element name="domain" type="xs:string"
minOccurs="1" maxOccurs="1"/>
<!-- The scope of the checked domain. -->
<xs:element name="scope" type="SPFDomainScope"
minOccurs="0" maxOccurs="1"/>
<!-- The SPF verification result. -->
<xs:element name="result" type="SPFResultType"
minOccurs="1" maxOccurs="1"/>
<!-- Any extra information (e.g., from Authentication-Results).
The information in the field below should be for a
person to be provided with additional information
that may be useful when debugging SPF authentication
issues. This could include broken records, invalid
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DNS responses, etc. -->
<xs:element name="human_result" type="xs:string"
minOccurs="0" maxOccurs="1"/>
</xs:all>
</xs:complexType>
<!-- This element contains DKIM and SPF results, uninterpreted
with respect to DMARC. -->
<xs:complexType name="AuthResultType">
<xs:sequence>
<!-- There may be zero or more DKIM signatures. -->
<xs:element name="dkim" type="DKIMAuthResultType"
minOccurs="0" maxOccurs="unbounded"/>
<!-- There may be zero or one SPF result. -->
<xs:element name="spf" type="SPFAuthResultType"
minOccurs="0" maxOccurs="1"/>
</xs:sequence>
</xs:complexType>
<!-- This element contains all the authentication results that
were evaluated by the receiving system for the given set of
messages. -->
<xs:complexType name="RecordType">
<xs:sequence>
<xs:element name="row" type="RowType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="identifiers" type="IdentifierType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="auth_results" type="AuthResultType"
minOccurs="1" maxOccurs="1"/>
<!-- Extension at record level -->
<xs:any processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="ExtensionType">
<xs:sequence>
<xs:any processContents="lax"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<!-- Parent -->
<xs:element name="feedback">
<xs:complexType>
<xs:sequence>
<xs:element name="version" type="xs:decimal"
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minOccurs="0" maxOccurs="1"/>
<xs:element name="report_metadata" type="ReportMetadataType"
minOccurs="1" maxOccurs="1"/>
<xs:element name="policy_published" type="PolicyPublishedType"
minOccurs="1" maxOccurs="1"/>
<!-- Extension at top level -->
<xs:element name="extension" type="ExtensionType"
minOccurs="0" maxOccurs="1"/>
<!-- One record per (IP, result, IDs Auths) tuples -->
<xs:element name="record" type="RecordType"
minOccurs="1" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Appendix B. Sample Report
<feedback xmlns="urn:ietf:params:xml:ns:dmarc-2.0">
<version>1.0</version>
<report_metadata>
<org_name>Sample Reporter</org_name>
<email>report_sender@example-reporter.com</email>
<extra_contact_info>...</extra_contact_info>
<report_id>3v98abbp8ya9n3va8yr8oa3ya</report_id>
<date_range>
<begin>302832000</begin>
<end>302918399</end>
</date_range>
<generator>Example DMARC Aggregate Reporter v1.2</generator>
</report_metadata>
<policy_published>
<domain>example.com</domain>
<p>quarantine</p>
<sp>none</sp>
<np>none</np>
<testing>n</testing>
<discovery_method>treewalk</discovery_method>
</policy_published>
<record>
<row>
<source_ip>192.0.2.123</source_ip>
<count>123</count>
<policy_evaluated>
<disposition>pass</disposition>
<dkim>pass</dkim>
<spf>fail</spf>
</policy_evaluated>
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</row>
<identifiers>
<envelope_from>example.com</envelope_from>
<header_from>example.com</header_from>
</identifiers>
<auth_results>
<dkim>
<domain>example.com</domain>
<result>pass</result>
<selector>abc123</selector>
</dkim>
<spf>
<domain>example.com</domain>
<result>fail</result>
</spf>
</auth_results>
</record>
</feedback>
Appendix C. Differences from RFC7489
A bulleted list of some of the more noticeable/important differences
between DMARC [RFC7489] and this document:
* Many elements of the defining XSD have been clarified, which means
the structure of the report should be more consistent
* The report identifier has more structure
* Clarification about the number of domains to be addressed per
report
* The addition of extensions as part of the report structure
* PSD is now included as part of the specification
* Selector is now required when reporting a DKIM signature
Furthermore, the original DMARC specification was contained within a
single document, [RFC7489]. The original document has been split
into three documents, DMARCbis [I-D.ietf-dmarc-dmarcbis], this
document [I-D.ietf-dmarc-aggregate-reporting], and DMARCbis Failure
Reporting [I-D.ietf-dmarc-failure-reporting]. This allows these
pieces to potentially be altered in the future without re-opening the
entire document, as well as allowing them to move through the IETF
process independently.
Acknowledgements
Many thanks are deserved to those that helped create this document.
Much of the content was created from the original [RFC7489], and has
now been updated to be more clear and correct some outstanding
issues. The IETF DMARC Working Group has spent much time working to
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finalize this effort, and significant contributions were made by Seth
Blank, Todd Herr, Steve Jones, Murray S. Kucherawy, Barry Leiba,
John Levine, Scott Kitterman, Daniel Kvå (U+00E5)l, Martijn van der
Lee, Alessandro Veseley, and Matthä (U+00E4)us Wander.
Author's Address
Alex Brotman
Comcast, Inc.
Email: alex_brotman@comcast.com
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