Files
parsedmarc/docs/source/output.md
Sean Whalen 2cda5bf59b Surface ASN info and use it for source attribution when a PTR is absent (#715)
* Surface ASN info and fall back to it when a PTR is absent

Adds three new fields to every IP source record — ``asn`` (integer,
e.g. 15169), ``asn_name`` (``"Google LLC"``), ``asn_domain``
(``"google.com"``) — sourced from the bundled IPinfo Lite MMDB. These
flow through to CSV, JSON, Elasticsearch, OpenSearch, and Splunk
outputs as ``source_asn``, ``source_asn_name``, ``source_asn_domain``.

More importantly: when an IP has no reverse DNS (common for many
large senders), source attribution now falls back to the ASN domain
as a lookup key into the same ``reverse_dns_map``. Thanks to #712
and #714, ~85% of routed IPv4 space now has an ``as_domain`` that
hits the map, so rows that were previously unattributable now get a
``source_name``/``source_type`` derived from the ASN. When the ASN
domain misses the map, the raw AS name is used as ``source_name``
with ``source_type`` left null — still better than nothing.

Crucially, ``source_reverse_dns`` and ``source_base_domain`` remain
null on ASN-derived rows, so downstream consumers can still tell a
PTR-resolved attribution apart from an ASN-derived one.

ASN is stored as an integer at the schema level (Elasticsearch /
OpenSearch mappings use ``Integer``) so consumers can do range
queries and numeric sorts; dashboards can prepend ``AS`` at display
time. The MMDB reader normalizes both IPinfo's ``"AS15169"`` string
and MaxMind's ``autonomous_system_number`` int to the same int form.

Also fixes a pre-existing caching bug in ``get_ip_address_info``:
entries without reverse DNS were never written to the IP-info cache,
so every no-PTR IP re-did the MMDB read and DNS attempt on every
call. The cache write is now unconditional.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Bump to 9.9.0 and document the ASN fallback work

Updates the changelog with a 9.9.0 entry covering the ASN-domain
aliases (#712, #714), map-maintenance tooling fixes (#713), and the
ASN-fallback source attribution added in this branch.

Extends AGENTS.md to explain that ``base_reverse_dns_map.csv`` is now
a mixed-namespace map (rDNS bases alongside ASN domains) and adds a
short recipe for finding high-value ASN-domain misses against the
bundled MMDB, so future contributors know where the map's second
lookup path comes from.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Document project conventions previously held only in agent memory

Promotes four conventions out of per-agent memory and into AGENTS.md
so every contributor — human or agent — works from the same baseline:

- Run ruff check + format before committing (Code Style).
- Store natively numeric values as numbers, not pre-formatted strings
  (e.g. ASN as int 15169, not "AS15169"; ES/OS mappings as Integer)
  (Code Style).
- Before rewriting a tracked list/data file from freshly-generated
  content, verify the existing content via git — these files
  accumulate manually-curated entries across sessions (Editing tracked
  data files).
- A release isn't done until hatch-built sdist + wheel are attached to
  the GitHub release page; full 8-step sequence documented (Releases).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Sean Whalen <seanthegeek@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-23 02:13:30 -04:00

9.4 KiB

Sample outputs

Sample aggregate report output

Here are the results from parsing the example report from the dmarc.org wiki. It's actually an older draft of the 1.0 report schema standardized in RFC 7480 Appendix C. This draft schema is still in wide use.

parsedmarc produces consistent, normalized output, regardless of the report schema.

JSON aggregate report

{
  "xml_schema": "draft",
  "report_metadata": {
    "org_name": "acme.com",
    "org_email": "noreply-dmarc-support@acme.com",
    "org_extra_contact_info": "http://acme.com/dmarc/support",
    "report_id": "9391651994964116463",
    "begin_date": "2012-04-27 20:00:00",
    "end_date": "2012-04-28 19:59:59",
    "timespan_requires_normalization": false,
    "original_timespan_seconds": 86399,
    "errors": []
  },
  "policy_published": {
    "domain": "example.com",
    "adkim": "r",
    "aspf": "r",
    "p": "none",
    "sp": "none",
    "pct": "100",
    "fo": "0"
  },
  "records": [
    {
      "source": {
        "ip_address": "72.150.241.94",
        "country": "US",
        "reverse_dns": null,
        "base_domain": null,
        "name": null,
        "type": null,
        "asn": 7018,
        "asn_name": "AT&T Services, Inc.",
        "asn_domain": "att.com"
      },
      "count": 2,
      "alignment": {
        "spf": true,
        "dkim": false,
        "dmarc": true
      },
      "policy_evaluated": {
        "disposition": "none",
        "dkim": "fail",
        "spf": "pass",
        "policy_override_reasons": []
      },
      "identifiers": {
        "header_from": "example.com",
        "envelope_from": "example.com",
        "envelope_to": null
      },
      "auth_results": {
        "dkim": [
          {
            "domain": "example.com",
            "selector": "none",
            "result": "fail"
          }
        ],
        "spf": [
          {
            "domain": "example.com",
            "scope": "mfrom",
            "result": "pass"
          }
        ]
      },
      "normalized_timespan": false,
      "interval_begin": "2012-04-28 00:00:00",
      "interval_end": "2012-04-28 23:59:59"
    }
  ]
}

CSV aggregate report

xml_schema,org_name,org_email,org_extra_contact_info,report_id,begin_date,end_date,normalized_timespan,errors,domain,adkim,aspf,p,sp,pct,fo,source_ip_address,source_country,source_reverse_dns,source_base_domain,source_name,source_type,source_asn,source_asn_name,source_asn_domain,count,spf_aligned,dkim_aligned,dmarc_aligned,disposition,policy_override_reasons,policy_override_comments,envelope_from,header_from,envelope_to,dkim_domains,dkim_selectors,dkim_results,spf_domains,spf_scopes,spf_results
draft,acme.com,noreply-dmarc-support@acme.com,http://acme.com/dmarc/support,9391651994964116463,2012-04-28 00:00:00,2012-04-28 23:59:59,False,,example.com,r,r,none,none,100,0,72.150.241.94,US,,,,,2,True,False,True,none,,,example.com,example.com,,example.com,none,fail,example.com,mfrom,pass
draft,acme.com,noreply-dmarc-support@acme.com,http://acme.com/dmarc/support,9391651994964116463,2012-04-28 00:00:00,2012-04-28 23:59:59,False,,example.com,r,r,none,none,100,0,72.150.241.94,US,,,,,2,True,False,True,none,,,example.com,example.com,,example.com,none,fail,example.com,mfrom,pass

Sample forensic report output

Thanks to GitHub user xennn for the anonymized forensic report email sample.

JSON forensic report

{
     "feedback_type": "auth-failure",
     "user_agent": "Lua/1.0",
     "version": "1.0",
     "original_mail_from": "sharepoint@domain.de",
     "original_rcpt_to": "peter.pan@domain.de",
     "arrival_date": "Mon, 01 Oct 2018 11:20:27 +0200",
     "message_id": "<38.E7.30937.BD6E1BB5@ mailrelay.de>",
     "authentication_results": "dmarc=fail (p=none, dis=none) header.from=domain.de",
     "delivery_result": "policy",
     "auth_failure": [
       "dmarc"
     ],
     "reported_domain": "domain.de",
     "arrival_date_utc": "2018-10-01 09:20:27",
     "source": {
       "ip_address": "10.10.10.10",
       "country": null,
       "reverse_dns": null,
       "base_domain": null,
       "name": null,
       "type": null,
       "asn": null,
       "asn_name": null,
       "asn_domain": null
     },
     "authentication_mechanisms": [],
     "original_envelope_id": null,
     "dkim_domain": null,
     "sample_headers_only": false,
     "sample": "Received: from Servernameone.domain.local (Servernameone.domain.local [10.10.10.10])\n\tby  mailrelay.de (mail.DOMAIN.de) with SMTP id 38.E7.30937.BD6E1BB5; Mon,  1 Oct 2018 11:20:27 +0200 (CEST)\nDate: 01 Oct 2018 11:20:27 +0200\nMessage-ID: <38.E7.30937.BD6E1BB5@ mailrelay.de>\nTo: <peter.pan@domain.de>\nfrom: \"=?utf-8?B?SW50ZXJha3RpdmUgV2V0dGJld2VyYmVyLcOcYmVyc2ljaHQ=?=\" <sharepoint@domain.de>\nSubject: Subject\nMIME-Version: 1.0\nX-Mailer: Microsoft SharePoint Foundation 2010\nContent-Type: text/html; charset=utf-8\nContent-Transfer-Encoding: quoted-printable\n\n<html><head><base href=3D'\nwettbewerb' /></head><body><!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 3.2//EN\"=\n><HTML><HEAD><META NAME=3D\"Generator\" CONTENT=3D\"MS Exchange Server version=\n 08.01.0240.003\"></html>\n",
     "parsed_sample": {
       "from": {
         "display_name": "Interaktive Wettbewerber-Übersicht",
         "address": "sharepoint@domain.de",
         "local": "sharepoint",
         "domain": "domain.de"
       },
       "to_domains": [
         "domain.de"
       ],
       "to": [
         {
           "display_name": null,
           "address": "peter.pan@domain.de",
           "local": "peter.pan",
           "domain": "domain.de"
         }
       ],
       "subject": "Subject",
       "timezone": "+2",
       "mime-version": "1.0",
       "date": "2018-10-01 09:20:27",
       "content-type": "text/html; charset=utf-8",
       "x-mailer": "Microsoft SharePoint Foundation 2010",
       "body": "<html><head><base href='\nwettbewerb' /></head><body><!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 3.2//EN\"><HTML><HEAD><META NAME=\"Generator\" CONTENT=\"MS Exchange Server version 08.01.0240.003\"></html>",
       "received": [
         {
           "from": "Servernameone.domain.local Servernameone.domain.local 10.10.10.10",
           "by": "mailrelay.de mail.DOMAIN.de",
           "with": "SMTP id 38.E7.30937.BD6E1BB5",
           "date": "Mon, 1 Oct 2018 11:20:27 +0200 CEST",
           "hop": 1,
           "date_utc": "2018-10-01 09:20:27",
           "delay": 0
         }
       ],
       "content-transfer-encoding": "quoted-printable",
       "message-id": "<38.E7.30937.BD6E1BB5@ mailrelay.de>",
       "has_defects": false,
       "headers": {
         "Received": "from Servernameone.domain.local (Servernameone.domain.local [10.10.10.10])\n\tby  mailrelay.de (mail.DOMAIN.de) with SMTP id 38.E7.30937.BD6E1BB5; Mon,  1 Oct 2018 11:20:27 +0200 (CEST)",
         "Date": "01 Oct 2018 11:20:27 +0200",
         "Message-ID": "<38.E7.30937.BD6E1BB5@ mailrelay.de>",
         "To": "<peter.pan@domain.de>",
         "from": "\"Interaktive Wettbewerber-Übersicht\" <sharepoint@domain.de>",
         "Subject": "Subject",
         "MIME-Version": "1.0",
         "X-Mailer": "Microsoft SharePoint Foundation 2010",
         "Content-Type": "text/html; charset=utf-8",
         "Content-Transfer-Encoding": "quoted-printable"
       },
       "reply_to": [],
       "cc": [],
       "bcc": [],
       "attachments": [],
       "filename_safe_subject": "Subject"
     }
   }

CSV forensic report

feedback_type,user_agent,version,original_envelope_id,original_mail_from,original_rcpt_to,arrival_date,arrival_date_utc,subject,message_id,authentication_results,dkim_domain,source_ip_address,source_country,source_reverse_dns,source_base_domain,source_name,source_type,source_asn,source_asn_name,source_asn_domain,delivery_result,auth_failure,reported_domain,authentication_mechanisms,sample_headers_only
auth-failure,Lua/1.0,1.0,,sharepoint@domain.de,peter.pan@domain.de,"Mon, 01 Oct 2018 11:20:27 +0200",2018-10-01 09:20:27,Subject,<38.E7.30937.BD6E1BB5@ mailrelay.de>,"dmarc=fail (p=none, dis=none) header.from=domain.de",,10.10.10.10,,,,policy,dmarc,domain.de,,False

JSON SMTP TLS report

[
  {
    "organization_name": "Example Inc.",
    "begin_date": "2024-01-09T00:00:00Z",
    "end_date": "2024-01-09T23:59:59Z",
    "report_id": "2024-01-09T00:00:00Z_example.com",
    "policies": [
      {
        "policy_domain": "example.com",
        "policy_type": "sts",
        "policy_strings": [
          "version: STSv1",
          "mode: testing",
          "mx: example.com",
          "max_age: 86400"
        ],
        "successful_session_count": 0,
        "failed_session_count": 3,
        "failure_details": [
          {
            "result_type": "validation-failure",
            "failed_session_count": 2,
            "sending_mta_ip": "209.85.222.201",
            "receiving_ip": "173.212.201.41",
            "receiving_mx_hostname": "example.com"
          },
          {
            "result_type": "validation-failure",
            "failed_session_count": 1,
            "sending_mta_ip": "209.85.208.176",
            "receiving_ip": "173.212.201.41",
            "receiving_mx_hostname": "example.com"
          }
        ]
      }
    ]
  }
]