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
2026-04-19 21:20:41 -04:00
2024-12-25 16:09:43 -05:00
2025-06-10 19:05:06 -04:00
2026-04-19 21:20:41 -04:00
2025-12-12 15:56:52 -05:00
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2018-02-05 20:23:07 -05:00
2022-10-04 18:45:57 -04:00
2026-03-09 18:24:16 -04:00

parsedmarc

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A screenshot of DMARC summary charts in Kibana

parsedmarc is a Python module and CLI utility for parsing DMARC reports. When used with Elasticsearch and Kibana (or Splunk), it works as a self-hosted open-source alternative to commercial DMARC report processing services such as Agari Brand Protection, Dmarcian, OnDMARC, ProofPoint Email Fraud Defense, and Valimail.

Note

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol.

Sponsors

This is a project is maintained by one developer. Please consider sponsoring my work if you or your organization benefit from it.

Features

  • Parses draft and 1.0 standard aggregate/rua DMARC reports
  • Parses forensic/failure/ruf DMARC reports
  • Parses reports from SMTP TLS Reporting
  • Can parse reports from an inbox over IMAP, Microsoft Graph, or Gmail API
  • Transparently handles gzip or zip compressed reports
  • Consistent data structures
  • Simple JSON and/or CSV output
  • Optionally email the results
  • Optionally send the results to Elasticsearch, Opensearch, and/or Splunk, for use with premade dashboards
  • Optionally send reports to Apache Kafka

Python Compatibility

This project supports the following Python versions, which are either actively maintained or are the default versions for RHEL or Debian.

Version Supported Reason
< 3.6 End of Life (EOL)
3.6 Used in RHEL 8, but not supported by project dependencies
3.7 End of Life (EOL)
3.8 End of Life (EOL)
3.9 Used in Debian 11 and RHEL 9, but not supported by project dependencies
3.10 Actively maintained
3.11 Actively maintained; supported until June 2028 (Debian 12)
3.12 Actively maintained; supported until May 2035 (RHEL 10)
3.13 Actively maintained; supported until June 2030 (Debian 13)
3.14 Supported (requires imapclient>=3.1.0)
Description
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