.. parsedmarc documentation master file, created by sphinx-quickstart on Mon Feb 5 18:25:39 2018. You can adapt this file completely to your liking, but it should at least contain the root `toctree` directive. =========================================================================== parsedmarc documentation - Open source DMARC report analyzer and visualizer =========================================================================== |Build Status| |Code Coverage| |PyPI Package| .. note:: **Help Wanted** This is a project is maintained by one developer. Please consider reviewing the open `issues`_ to see how you can contribute code, documentation, or user support. Assistance on the pinned issues would be particularly helpful. Thanks to all `contributors`_! .. image:: _static/screenshots/dmarc-summary-charts.png :alt: A screenshot of DMARC summary charts in Kibana :scale: 50 % :align: center :target: _static/screenshots/dmarc-summary-charts.png ``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. Features ======== * Parses draft and 1.0 standard aggregate/rua reports * Parses forensic/failure/ruf reports * 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 and/or Splunk, for use with premade dashboards * Optionally send reports to Apache Kafka Resources ========= DMARC guides ------------ * `Demystifying DMARC`_ - A complete guide to SPF, DKIM, and DMARC SPF and DMARC record validation ------------------------------- If you are looking for SPF and DMARC record validation and parsing, check out the sister project, `checkdmarc `_. Lookalike domains ----------------- DMARC protects against domain spoofing, not lookalike domains. for open source lookalike domain monitoring, check out `DomainAware `_. CLI help ======== .. code-block:: text usage: parsedmarc [-h] [-c CONFIG_FILE] [--strip-attachment-payloads] [-o OUTPUT] [--aggregate-json-filename AGGREGATE_JSON_FILENAME] [--forensic-json-filename FORENSIC_JSON_FILENAME] [--aggregate-csv-filename AGGREGATE_CSV_FILENAME] [--forensic-csv-filename FORENSIC_CSV_FILENAME] [-n NAMESERVERS [NAMESERVERS ...]] [-t DNS_TIMEOUT] [--offline] [-s] [--verbose] [--debug] [--log-file LOG_FILE] [-v] [file_path ...] Parses DMARC reports positional arguments: file_path one or more paths to aggregate or forensic report files, emails, or mbox files' optional arguments: -h, --help show this help message and exit -c CONFIG_FILE, --config-file CONFIG_FILE a path to a configuration file (--silent implied) --strip-attachment-payloads remove attachment payloads from forensic report output -o OUTPUT, --output OUTPUT write output files to the given directory --aggregate-json-filename AGGREGATE_JSON_FILENAME filename for the aggregate JSON output file --forensic-json-filename FORENSIC_JSON_FILENAME filename for the forensic JSON output file --aggregate-csv-filename AGGREGATE_CSV_FILENAME filename for the aggregate CSV output file --forensic-csv-filename FORENSIC_CSV_FILENAME filename for the forensic CSV output file -n NAMESERVERS [NAMESERVERS ...], --nameservers NAMESERVERS [NAMESERVERS ...] nameservers to query -t DNS_TIMEOUT, --dns_timeout DNS_TIMEOUT number of seconds to wait for an answer from DNS (default: 2.0) --offline do not make online queries for geolocation or DNS -s, --silent only print errors and warnings --verbose more verbose output --debug print debugging information --log-file LOG_FILE output logging to a file -v, --version show program's version number and exit .. note:: Starting in ``parsedmarc`` 6.0.0, most CLI options were moved to a configuration file, described below. Configuration file ================== ``parsedmarc`` can be configured by supplying the path to an INI file .. code-block:: bash parsedmarc -c /etc/parsedmarc.ini For example .. code-block:: ini # This is an example comment [general] save_aggregate = True save_forensic = True [imap] host = imap.example.com user = dmarcresports@example.com password = $uperSecure [mailbox] watch = True delete = False [elasticsearch] hosts = 127.0.0.1:9200 ssl = False [splunk_hec] url = https://splunkhec.example.com token = HECTokenGoesHere index = email [s3] bucket = my-bucket path = parsedmarc [syslog] server = localhost port = 514 The full set of configuration options are: - ``general`` - ``save_aggregate`` - bool: Save aggregate report data to Elasticsearch, Splunk and/or S3 - ``save_forensic`` - bool: Save forensic report data to Elasticsearch, Splunk and/or S3 - ``strip_attachment_payloads`` - bool: Remove attachment payloads from results - ``output`` - str: Directory to place JSON and CSV files in - ``aggregate_json_filename`` - str: filename for the aggregate JSON output file - ``forensic_json_filename`` - str: filename for the forensic JSON output file - ``ip_db_path`` - str: An optional custom path to a MMDB file - from MaxMind or DBIP - ``offline`` - bool: Do not use online queries for geolocation or DNS - ``nameservers`` - str: A comma separated list of DNS resolvers (Default: `Cloudflare's public resolvers`_) - ``dns_timeout`` - float: DNS timeout period - ``debug`` - bool: Print debugging messages - ``silent`` - bool: Only print errors (Default: True) - ``log_file`` - str: Write log messages to a file at this path - ``n_procs`` - int: Number of process to run in parallel when parsing in CLI mode (Default: 1) - ``chunk_size`` - int: Number of files to give to each process when running in parallel. .. note:: Setting this to a number larger than one can improve performance when processing thousands of files - ``mailbox`` - ``reports_folder`` - str: The mailbox folder (or label for Gmail) where the incoming reports can be found (Default: INBOX) - ``archive_folder`` - str: The mailbox folder (or label for Gmail) to sort processed emails into (Default: Archive) - ``watch`` - bool: Use the IMAP ``IDLE`` command to process - messages as they arrive or poll MS Graph for new messages - ``delete`` - bool: Delete messages after processing them, - instead of archiving them - ``test`` - bool: Do not move or delete messages - ``batch_size`` - int: Number of messages to read and process before saving. Default 10. Use 0 for no limit. - ``check_timeout`` - int: Number of seconds to wait for a IMAP IDLE response or the number of seconds until the next mai check (Default: 30) - ``imap`` - ``host`` - str: The IMAP server hostname or IP address - ``port`` - int: The IMAP server port (Default: 993) .. note:: ``%`` characters must be escaped with another ``%`` character, so use ``%%`` wherever a ``%`` character is used. .. note:: Starting in version 8.0.0, most options from the ``imap`` section have been moved to the ``mailbox`` section. .. note:: If your host recommends another port, still try 993 - ``ssl`` - bool: Use an encrypted SSL/TLS connection (Default: True) - ``skip_certificate_verification`` - bool: Skip certificate verification (not recommended) - ``user`` - str: The IMAP user - ``password`` - str: The IMAP password - ``msgraph`` - ``auth_method`` - str: Authentication method, valid types are UsernamePassword, DeviceCode, or ClientSecret (Default: UsernamePassword). - ``user`` - str: The M365 user, required when the auth method is UsernamePassword - ``password`` - str: The user password, required when the auth method is UsernamePassword - ``client_id`` - str: The app registration's client ID - ``client_secret`` - str: The app registration's secret - ``tenant_id`` - str: The Azure AD tenant ID. This is required for all auth methods except UsernamePassword. - ``mailbox`` - str: The mailbox name. This defaults to the current user if using the UsernamePassword auth method, but could be a shared mailbox if the user has access to the mailbox - ``token_file`` - str: Path to save the token file (Default: .token) .. note:: You must create an app registration in Azure AD and have an admin grant the Microsoft Graph ``Mail.ReadWrite`` (delegated) permission to the app. If you are using `UsernamePassword` auth and the mailbox is different from the username, you must grant the app ``Mail.ReadWrite.Shared``. .. warning:: If you are using the `ClientSecret` auth method, you need to grant the ``Mail.ReadWrite`` (application) permission to the app. You must also restrict the application's access to a specific mailbox since it allows all mailboxes by default. Use the ``New-ApplicationAccessPolicy`` command in the Exchange PowerShell module. If you need to scope the policy to shared mailboxes, you can add them to a mail enabled security group and use that as the group id. .. code-block:: powershell New-ApplicationAccessPolicy -AccessRight RestrictAccess -AppId "" -PolicyScopeGroupId "" -Description "Restrict access to dmarc reports mailbox." - ``elasticsearch`` - ``hosts`` - str: A comma separated list of hostnames and ports or URLs (e.g. ``127.0.0.1:9200`` or ``https://user:secret@localhost``) .. note:: Special characters in the username or password must be `URL encoded`_. - ``ssl`` - bool: Use an encrypted SSL/TLS connection (Default: True) - ``cert_path`` - str: Path to a trusted certificates - ``index_suffix`` - str: A suffix to apply to the index names - ``monthly_indexes`` - bool: Use monthly indexes instead of daily indexes - ``number_of_shards`` - int: The number of shards to use when creating the index (Default: 1) - ``number_of_replicas`` - int: The number of replicas to use when creating the index (Default: 1) - ``splunk_hec`` - ``url`` - str: The URL of the Splunk HTTP Events Collector (HEC) - ``token`` - str: The HEC token - ``index`` - str: The Splunk index to use - ``skip_certificate_verification`` - bool: Skip certificate verification (not recommended) - ``kafka`` - ``hosts`` - str: A comma separated list of Kafka hosts - ``user`` - str: The Kafka user - ``passsword`` - str: The Kafka password - ``ssl`` - bool: Use an encrypted SSL/TLS connection (Default: True) - ``skip_certificate_verification`` - bool: Skip certificate verification (not recommended) - ``aggregate_topic`` - str: The Kafka topic for aggregate reports - ``forensic_topic`` - str: The Kafka topic for forensic reports - ``smtp`` - ``host`` - str: The SMTP hostname - ``port`` - int: The SMTP port (Default: 25) - ``ssl`` - bool: Require SSL/TLS instead of using STARTTLS - ``skip_certificate_verification`` - bool: Skip certificate verification (not recommended) - ``user`` - str: the SMTP username - ``password`` - str: the SMTP password - ``from`` - str: The From header to use in the email - ``to`` - list: A list of email addresses to send to - ``subject`` - str: The Subject header to use in the email (Default: parsedmarc report) - ``attachment`` - str: The ZIP attachment filenames - ``message`` - str: The email message (Default: Please see the attached parsedmarc report.) .. note:: ``%`` characters must be escaped with another ``%`` character, so use ``%%`` wherever a ``%`` character is used. - ``s3`` - ``bucket`` - str: The S3 bucket name - ``path`` - str: The path to upload reports to (Default: /) - ``region_name`` - str: The region name (Optional) - ``endpoint_url`` - str: The endpoint URL (Optional) - ``access_key_id`` - str: The access key id (Optional) - ``secret_access_key`` - str: The secret access key (Optional) - ``syslog`` - ``server`` - str: The Syslog server name or IP address - ``port`` - int: The UDP port to use (Default: 514) - ``gmail_api`` - ``credentials_file`` - str: Path to file containing the credentials, None to disable (Default: None) - ``token_file`` - str: Path to save the token file (Default: .token) - ``include_spam_trash`` - bool: Include messages in Spam and Trash when searching reports (Default: False) - ``scopes`` - str: Comma separated list of scopes to use when acquiring credentials (Default: https://www.googleapis.com/auth/gmail.modify) - ``oauth2_port`` - int: The TCP port for the local server to listen on for the OAuth2 response (Default: 8080) .. warning:: It is **strongly recommended** to **not** use the ``nameservers`` setting. By default, ``parsedmarc`` uses `Cloudflare's public resolvers`_, which are much faster and more reliable than Google, Cisco OpenDNS, or even most local resolvers. The ``nameservers`` option should only be used if your network blocks DNS requests to outside resolvers. .. warning:: ``save_aggregate`` and ``save_forensic`` are separate options because you may not want to save forensic reports (also known as failure reports) to your Elasticsearch instance, particularly if you are in a highly-regulated industry that handles sensitive data, such as healthcare or finance. If your legitimate outgoing email fails DMARC, it is possible that email may appear later in a forensic report. Forensic reports contain the original headers of an email that failed a DMARC check, and sometimes may also include the full message body, depending on the policy of the reporting organization. Most reporting organizations do not send forensic reports of any kind for privacy reasons. While aggregate DMARC reports are sent at least daily, it is normal to receive very few forensic reports. An alternative approach is to still collect forensic/failure/ruf reports in your DMARC inbox, but run ``parsedmarc`` with ``save_forensic = True``manually on a separate IMAP folder (using the ``reports_folder`` option), after you have manually moved known samples you want to save to that folder (e.g. malicious samples and non-sensitive legitimate samples). 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 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 ---- .. code-block:: json { "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", "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": "adsl-72-150-241-94.shv.bellsouth.net", "base_domain": "bellsouth.net" }, "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" } ] } } ] } CSV --- .. code-block:: text xml_schema,org_name,org_email,org_extra_contact_info,report_id,begin_date,end_date,errors,domain,adkim,aspf,p,sp,pct,fo,source_ip_address,source_country,source_reverse_dns,source_base_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,9391651994964116463,2012-04-27 20:00:00,2012-04-28 19:59:59,,example.com,r,r,none,none,100,0,72.150.241.94,US,adsl-72-150-241-94.shv.bellsouth.net,bellsouth.net,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 ---- .. code-block:: json { "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 }, "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: \nfrom: \"=?utf-8?B?SW50ZXJha3RpdmUgV2V0dGJld2VyYmVyLcOcYmVyc2ljaHQ=?=\" \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\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": "", "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": "", "from": "\"Interaktive Wettbewerber-Übersicht\" ", "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 --- .. code-block:: text 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,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 Bug reports =========== Please report bugs on the GitHub issue tracker https://github.com/domainaware/parsedmarc/issues Installation ============ ``parsedmarc`` works with Python 3 only. .. note:: If your system is behind a web proxy, you need to configure your system to use that proxy. To do this, edit ``/etc/environment`` and add your proxy details there, for example: .. code-block:: bash http_proxy=http://user:password@prox-server:3128 https_proxy=https://user:password@prox-server:3128 ftp_proxy=http://user:password@prox-server:3128 Or if no credentials are needed: .. code-block:: bash http_proxy=http://prox-server:3128 https_proxy=https://prox-server:3128 ftp_proxy=http://prox-server:3128 This will set the the proxy up for use system-wide, including for ``parsedmarc``. .. warning:: If your mail server is Microsoft Exchange, ensure that it is patched to at least: - Exchange Server 2010 Update Rollup 22 (`KB4295699 `_) - Exchange Server 2013 Cumulative Update 21 (`KB4099855 `_) - Exchange Server 2016 Cumulative Update 11 (`KB4134118 `_) geoipupdate setup ----------------- .. note:: Starting in ``parsedmarc`` 7.1.0, a static copy of the `IP to Country Lite database`_ from IPDB is distributed with ``parsedmarc``, under the terms of the `Creative Commons Attribution 4.0 International License`_. as a fallback if the `MaxMind GeoLite2 Country database`_ is not installed However, ``parsedmarc`` cannot install updated versions of these databases as they are released, so MaxMind's databases and `geoipupdate`_ tool is still the preferable solution. The location of the database file can be overridden by using the ``ip_db_path`` setting. On Debian 10 (Buster) or later, run: .. code-block:: bash sudo apt-get install -y geoipupdate On Ubuntu systems run: .. code-block:: bash sudo add-apt-repository ppa:maxmind/ppa sudo apt update sudo apt install -y geoipupdate On CentOS or RHEL systems, run: .. code-block:: bash sudo dnf install -y geoipupdate The latest builds for Linux, macOS, and Windows can be downloaded from the `geoipupdate releases page on GitHub`_. On December 30th, 2019, MaxMind started requiring free accounts to access the free Geolite2 databases, in order `to comply with various privacy regulations`_. Start by `registering for a free GeoLite2 account`_, and signing in. Then, navigate the to the `License Keys`_ page under your account, and create a new license key for the version of ``geoipupdate`` that was installed. .. warning:: The configuration file format is different for older (i.e. <=3.1.1) and newer (i.e. >=3.1.1) versions of ``geoipupdate``. Be sure to select the correct version for your system. .. note:: To check the version of ``geoipupdate`` that is installed, run: .. code-block:: bash geoipupdate -V You can use ``parsedmarc`` as the description for the key. Once you have generated a key, download the config pre-filled configuration file. This file should be saved at ``/etc/GeoIP.conf`` on Linux or macOS systems, or at ``%SystemDrive%\ProgramData\MaxMind\GeoIPUpdate\GeoIP.conf`` on Windows systems. Then run .. code-block:: bash sudo geoipupdate To download the databases for the first time. The GeoLite2 Country, City, and ASN databases are updated weekly, every Tuesday. ``geoipupdate`` can be run weekly by adding a cron job or scheduled task. More information about ``geoipupdate`` can be found at the `MaxMind geoipupdate page`_. Installing parsedmarc --------------------- On Debian or Ubuntu systems, run: .. code-block:: bash sudo apt-get install -y python3-pip python3-virtualenv python3-dev libxml2-dev libxslt-dev On CentOS or RHEL systems, run: .. code-block:: bash sudo dnf install -y python39 python3-virtualenv python3-setuptools python3-devel libxml2-devel libxslt-devel Python 3 installers for Windows and macOS can be found at https://www.python.org/downloads/ Create a system user .. code-block:: bash sudo mkdir /opt sudo useradd parsedmarc -r -s /bin/false -m -b /opt Install parsedmarc in a virtualenv .. code-block:: bash sudo -u parsedmarc virtualenv /opt/parsedmarc/venv CentOS/RHEL 8 systems use Python 3.6 by default, so on those systems explicitly tell ``virtualenv`` to use ``python3.9`` instead .. code-block:: bash sudo -u parsedmarc virtualenv -p python3.9 /opt/parsedmarc/venv To install or upgrade ``parsedmarc`` inside the virtualenv, run: .. code-block:: bash sudo -u parsedmarc /opt/parsedmarc/venv -U parsedmarc Optional dependencies --------------------- If you would like to be able to parse emails saved from Microsoft Outlook (i.e. OLE .msg files), install ``msgconvert``: On Debian or Ubuntu systems, run: .. code-block:: bash sudo apt-get install libemail-outlook-message-perl Testing multiple report analyzers --------------------------------- If you would like to test parsedmarc and another report processing solution at the same time, you can have up to two mailto URIs each in the rua and ruf tags in your DMARC record, separated by commas. Accessing an inbox using OWA/EWS -------------------------------- .. note:: Starting in 8.0.0, parsedmarc supports accessing Microsoft/Office 365 inboxes via the Microsoft Graph API, which is preferred over Davmail. Some organizations do not allow IMAP or the Microsoft Graph API, and only support Exchange Web Services (EWS)/Outlook Web Access (OWA). In that case, Davmail will need to be set up as a local EWS/OWA IMAP gateway. It can even work where `Modern Auth/multi-factor authentication`_ is required. To do this, download the latest ``davmail-version.zip`` from https://sourceforge.net/projects/davmail/files/ Extract the zip using the ``unzip`` command. Install Java: .. code-block:: bash sudo apt-get install default-jre-headless Configure Davmail by creating a ``davmail.properties`` file .. code-block:: properties # DavMail settings, see http://davmail.sourceforge.net/ for documentation ############################################################# # Basic settings # Server or workstation mode davmail.server=true # connection mode auto, EWS or WebDav davmail.enableEws=auto # base Exchange OWA or EWS url davmail.url=https://outlook.office365.com/EWS/Exchange.asmx # Listener ports davmail.imapPort=1143 ############################################################# # Network settings # Network proxy settings davmail.enableProxy=false davmail.useSystemProxies=false davmail.proxyHost= davmail.proxyPort= davmail.proxyUser= davmail.proxyPassword= # proxy exclude list davmail.noProxyFor= # block remote connection to DavMail davmail.allowRemote=false # bind server sockets to the loopback address davmail.bindAddress=127.0.0.1 # disable SSL for specified listeners davmail.ssl.nosecureimap=true # Send keepalive character during large folder and messages download davmail.enableKeepalive=true # Message count limit on folder retrieval davmail.folderSizeLimit=0 ############################################################# # IMAP settings # Delete messages immediately on IMAP STORE \Deleted flag davmail.imapAutoExpunge=true # Enable IDLE support, set polling delay in minutes davmail.imapIdleDelay=1 # Always reply to IMAP RFC822.SIZE requests with Exchange approximate # message size for performance reasons davmail.imapAlwaysApproxMsgSize=true # Client connection timeout in seconds - default 300, 0 to disable davmail.clientSoTimeout=0 ############################################################# Running DavMail as a systemd service ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Use systemd to run ``davmail`` as a service. Create a system user .. code-block:: bash sudo useradd davmail -r -s /bin/false Protect the ``davmail`` configuration file from prying eyes .. code-block:: bash sudo chown root:davmail /opt/davmail/davmail.properties sudo chmod u=rw,g=r,o= /opt/davmail/davmail.properties Create the service configuration file .. code-block:: bash sudo nano /etc/systemd/system/davmail.service .. code-block:: ini [Unit] Description=DavMail gateway service Documentation=https://sourceforge.net/projects/davmail/ Wants=network-online.target After=syslog.target network.target [Service] ExecStart=/opt/davmail/davmail /opt/davmail/davmail.properties User=davmail Group=davmail Restart=always RestartSec=5m [Install] WantedBy=multi-user.target Then, enable the service .. code-block:: bash sudo systemctl daemon-reload sudo systemctl enable parsedmarc.service sudo service davmail restart .. note:: You must also run the above commands whenever you edit ``davmail.service``. .. warning:: Always restart the service every time you upgrade to a new version of ``davmail``: .. code-block:: bash sudo service davmail restart To check the status of the service, run: .. code-block:: bash service davmail status .. note:: In the event of a crash, systemd will restart the service after 5 minutes, but the `service davmail status` command will only show the logs for the current process. To vew the logs for previous runs as well as the current process (newest to oldest), run: .. code-block:: bash journalctl -u davmail.service -r Configuring parsedmarc for DavMail ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Because you are interacting with DavMail server over the loopback (i.e. ``127.0.0.1``), add the following options to ``parsedmarc.ini`` config file: .. code-block:: ini [imap] host=127.0.0.1 port=1143 ssl=False watch=True Elasticsearch and Kibana ------------------------ .. note:: Splunk is also supported starting with ``parsedmarc`` 4.3.0 To set up visual dashboards of DMARC data, install Elasticsearch and Kibana. .. note:: Elasticsearch and Kibana 6 or later are required On Debian/Ubuntu based systems, run: .. code-block:: bash sudo apt-get install -y apt-transport-https wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add - echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list sudo apt-get update sudo apt-get install -y default-jre-headless elasticsearch kibana For CentOS, RHEL, and other RPM systems, follow the Elastic RPM guides for `Elasticsearch`_ and `Kibana`_. .. warning:: The default JVM heap size for Elasticsearch is very small (1g), which will cause it to crash under a heavy load. To fix this, increase the minimum and maximum JVM heap sizes in ``/etc/elasticsearch/jvm.options`` to more reasonable levels, depending on your server's resources. Make sure the system has at least 2 GB more RAM then the assigned JVM heap size. Always set the minimum and maximum JVM heap sizes to the same value. For example, to set a 4 GB heap size, set .. code-block:: bash -Xms4g -Xmx4g See https://www.elastic.co/guide/en/elasticsearch/reference/current/heap-size.html for more information. .. code-block:: bash sudo systemctl daemon-reload sudo systemctl enable elasticsearch.service sudo systemctl enable kibana.service sudo service elasticsearch start sudo service kibana start Without the commercial X-Pack_ or ReadonlyREST_ products, Kibana does not have any authentication mechanism of its own. You can use nginx as a reverse proxy that provides basic authentication. .. code-block:: bash sudo apt-get install -y nginx apache2-utils Or, on CentOS: .. code-block:: bash sudo yum install -y nginx httpd-tools Create a directory to store the certificates and keys: .. code-block:: bash mkdir ~/ssl cd ~/ssl To create a self-signed certificate, run: .. code-block:: bash openssl req -x509 -nodes -days 365 -newkey rsa:4096 -keyout kibana.key -out kibana.crt Or, to create a Certificate Signing Request (CSR) for a CA, run: .. code-block:: bash openssl req -newkey rsa:4096-nodes -keyout kibana.key -out kibana.csr Fill in the prompts. Watch out for Common Name (e.g. server FQDN or YOUR domain name), which is the IP address or domain name that you will be hosting Kibana on. it is the most important field. If you generated a CSR, remove the CSR after you have your certs .. code-block:: bash rm -f kibana.csr Move the keys into place and secure them: .. code-block:: bash cd sudo mv ssl /etc/nginx sudo chown -R root:www-data /etc/nginx/ssl sudo chmod -R u=rX,g=rX,o= /etc/nginx/ssl Disable the default nginx configuration: .. code-block:: bash sudo rm /etc/nginx/sites-enabled/default Create the web server configuration .. code-block:: bash sudo nano /etc/nginx/sites-available/kibana .. code-block:: nginx server { listen 443 ssl http2; ssl_certificate /etc/nginx/ssl/kibana.crt; ssl_certificate_key /etc/nginx/ssl/kibana.key; ssl_session_timeout 1d; ssl_session_cache shared:SSL:50m; ssl_session_tickets off; # modern configuration. tweak to your needs. ssl_protocols TLSv1.2; ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256'; ssl_prefer_server_ciphers on; # Uncomment this next line if you are using a signed, trusted cert #add_header Strict-Transport-Security "max-age=63072000; includeSubdomains; preload"; add_header X-Frame-Options SAMEORIGIN; add_header X-Content-Type-Options nosniff; auth_basic "Login required"; auth_basic_user_file /etc/nginx/htpasswd; location / { proxy_pass http://127.0.0.1:5601; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; } } server { listen 80; return 301 https://$host$request_uri; } Enable the nginx configuration for Kibana: .. code-block:: bash sudo ln -s /etc/nginx/sites-available/kibana /etc/nginx/sites-enabled/kibana Add a user to basic authentication: .. code-block:: bash sudo htpasswd -c /etc/nginx/htpasswd exampleuser Where ``exampleuser`` is the name of the user you want to add. Secure the permissions of the httpasswd file: .. code-block:: bash sudo chown root:www-data /etc/nginx/htpasswd sudo chmod u=rw,g=r,o= /etc/nginx/htpasswd Restart nginx: .. code-block:: bash sudo service nginx restart Now that Elasticsearch is up and running, use ``parsedmarc`` to send data to it. Download (right click the link and click save as) export.ndjson_. Import ``export.ndjson`` the Saved Objects tab of the Stack management page of Kibana. It will give you the option to overwrite existing saved dashboards or visualizations, which could be used to restore them if you or someone else breaks them, as there are no permissions/access controls in Kibana without the commercial X-Pack_. .. image:: _static/screenshots/saved-objects.png :alt: A screenshot of setting the Saved Objects Stack management UI in Kibana :align: center :target: _static/screenshots/saved-objects.png .. image:: _static/screenshots/confirm-overwrite.png :alt: A screenshot of the overwrite conformation prompt :align: center :target: _static/screenshots/confirm-overwrite.png Upgrading Kibana index patterns ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``parsedmarc`` 5.0.0 makes some changes to the way data is indexed in Elasticsearch. if you are upgrading from a previous release of ``parsedmarc``, you need to complete the following steps to replace the Kibana index patterns with versions that match the upgraded indexes: 1. Login in to Kibana, and click on Management 2. Under Kibana, click on Saved Objects 3. Check the checkboxes for the ``dmarc_aggregate`` and ``dmarc_forensic`` index patterns 4. Click Delete 5. Click Delete on the conformation message 6. Download (right click the link and click save as) the latest version of export.ndjson_ 7. Import ``export.ndjson`` by clicking Import from the Kibana Saved Objects page Records retention ~~~~~~~~~~~~~~~~~ Starting in version 5.0.0, ``parsedmarc`` stores data in a separate index for each day to make it easy to comply with records retention regulations such as GDPR. For fore information, check out the Elastic guide to `managing time-based indexes efficiently `_. Splunk ------ Starting in version 4.3.0 ``parsedmarc`` supports sending aggregate and/or forensic DMARC data to a Splunk `HTTP Event collector (HEC)`_. The project repository contains `XML files`_ for premade Splunk dashboards for aggregate and forensic DMARC reports. Copy and paste the contents of each file into a separate Splunk dashboard XML editor. .. warning:: Change all occurrences of ``index="email"`` in the XML to match your own index name. The Splunk dashboards display the same content and layout as the Kibana dashboards, although the Kibana dashboards have slightly easier and more flexible filtering options. Running parsedmarc as a systemd service --------------------------------------- Use systemd to run ``parsedmarc`` as a service and process reports as they arrive. Protect the ``parsedmarc`` configuration file from prying eyes .. code-block:: bash sudo chown root:parsedmarc /etc/parsedmarc.ini sudo chmod u=rw,g=r,o= /etc/parsedmarc.ini Create the service configuration file .. code-block:: bash sudo nano /etc/systemd/system/parsedmarc.service .. code-block:: ini [Unit] Description=parsedmarc mailbox watcher Documentation=https://domainaware.github.io/parsedmarc/ Wants=network-online.target After=network.target network-online.target elasticsearch.service [Service] ExecStart=/opt/parsedmarc/venv/bin/parsedmarc -c /etc/parsedmarc.ini User=parsedmarc Group=parsedmarc Restart=always RestartSec=5m [Install] WantedBy=multi-user.target Then, enable the service .. code-block:: bash sudo systemctl daemon-reload sudo systemctl enable parsedmarc.service sudo service parsedmarc restart .. note:: You must also run the above commands whenever you edit ``parsedmarc.service``. .. warning:: Always restart the service every time you upgrade to a new version of ``parsedmarc``: .. code-block:: bash sudo service parsedmarc restart To check the status of the service, run: .. code-block:: bash service parsedmarc status .. note:: In the event of a crash, systemd will restart the service after 10 minutes, but the `service parsedmarc status` command will only show the logs for the current process. To vew the logs for previous runs as well as the current process (newest to oldest), run: .. code-block:: bash journalctl -u parsedmarc.service -r Using the Kibana dashboards =========================== The Kibana DMARC dashboards are a human-friendly way to understand the results from incoming DMARC reports. .. note:: The default dashboard is DMARC Summary. To switch between dashboards, click on the Dashboard link in the left side menu of Kibana. DMARC Summary ------------- As the name suggests, this dashboard is the best place to start reviewing your aggregate DMARC data. Across the top of the dashboard, three pie charts display the percentage of alignment pass/fail for SPF, DKIM, and DMARC. Clicking on any chart segment will filter for that value. .. note:: Messages should not be considered malicious just because they failed to pass DMARC; especially if you have just started collecting data. It may be a legitimate service that needs SPF and DKIM configured correctly. Start by filtering the results to only show failed DKIM alignment. While DMARC passes if a message passes SPF or DKIM alignment, only DKIM alignment remains valid when a message is forwarded without changing the from address, which is often caused by a mailbox forwarding rule. This is because DKIM signatures are part of the message headers, whereas SPF relies on SMTP session headers. Underneath the pie charts. you can see graphs of DMARC passage and message disposition over time. Under the graphs you will find the most useful data tables on the dashboard. On the left, there is a list of organizations that are sending you DMARC reports. In the center, there is a list of sending servers grouped by the base domain in their reverse DNS. On the right, there is a list of email from domains, sorted by message volume. By hovering your mouse over a data table value and using the magnifying glass icons, you can filter on our filter out different values. Start by looking at the Message Sources by Reverse DNS table. Find a sender that you recognize, such as an email marketing service, hover over it, and click on the plus (+) magnifying glass icon, to add a filter that only shows results for that sender. Now, look at the Message From Header table to the right. That shows you the domains that a sender is sending as, which might tell you which brand/business is using a particular service. With that information, you can contact them and have them set up DKIM. .. note:: If you have a lot of B2C customers, you may see a high volume of emails as your domains coming from consumer email services, such as Google/Gmail and Yahoo! This occurs when customers have mailbox rules in place that forward emails from an old account to a new account, which is why DKIM authentication is so important, as mentioned earlier. Similar patterns may be observed with businesses who send from reverse DNS addressees of parent, subsidiary, and outdated brands. Further down the dashboard, you can filter by source country or source IP address. Tables showing SPF and DKIM alignment details are located under the IP address table. .. note:: Previously, the alignment tables were included in a separate dashboard called DMARC Alignment Failures. That dashboard has been consolidated into the DMARC Summary dashboard. To view failures only, use the pie chart. Any other filters work the same way. You can also add your own custom temporary filters by clicking on Add Filter at the upper right of the page. DMARC Forensic Samples ---------------------- The DMARC Forensic Samples dashboard contains information on DMARC forensic reports (also known as failure reports or ruf reports). These reports contain samples of emails that have failed to pass DMARC. .. note:: Most recipients do not send forensic/failure/ruf reports at all to avoid privacy leaks. Some recipients (notably Chinese webmail services) will only supply the headers of sample emails. Very few provide the entire email. DMARC Alignment Guide ===================== DMARC ensures that SPF and DKM authentication mechanisms actually authenticate against the same domain that the end user sees. A message passes a DMARC check by passing DKIM or SPF, **as long as the related indicators are also in alignment**. +-----------------------+-----------------------+-----------------------+ | | **DKIM** | **SPF** | +-----------------------+-----------------------+-----------------------+ | **Passing** | The signature in the | The mail server's IP | | | DKIM header is | address is listed in | | | validated using a | the SPF record of the | | | public key that is | domain in the SMTP | | | published as a DNS | envelope's mail from | | | record of the domain | header | | | name specified in the | | | | signature | | +-----------------------+-----------------------+-----------------------+ | **Alignment** | The signing domain | The domain in the | | | aligns with the | SMTP envelope's mail | | | domain in the | from header aligns | | | message's from header | with the domain in | | | | the message's from | | | | header | +-----------------------+-----------------------+-----------------------+ What if a sender won't support DKIM/DMARC? ========================================== #. Some vendors don't know about DMARC yet; ask about SPF and DKIM/email authentication. #. Check if they can send through your email relays instead of theirs. #. Do they really need to spoof your domain? Why not use the display name instead? #. Worst case, have that vendor send email as a specific subdomain of your domain (e.g. ``noreply@news.example.com``), and then create separate SPF and DMARC records on ``news.example.com``, and set ``p=none`` in that DMARC record. .. warning :: Do not alter the ``p`` or ``sp`` values of the DMARC record on the Top-Level Domain (TLD) – that would leave you vulnerable to spoofing of your TLD and/or any subdomain. What about mailing lists? ========================= When you deploy DMARC on your domain, you might find that messages relayed by mailing lists are failing DMARC, most likely because the mailing list is spoofing your from address, and modifying the subject, footer, or other part of the message, thereby breaking the DKIM signature. Mailing list list best practices -------------------------------- Ideally, a mailing list should forward messages without altering the headers or body content at all. `Joe Nelson`_ does a fantastic job of explaining exactly what mailing lists should and shouldn't do to be fully DMARC compliant. Rather than repeat his fine work, here's a summary: **Do** - Retain headers from the original message - Add `RFC 2369`_ List-Unsubscribe headers to outgoing messages, instead of adding unsubscribe links to the body :: List-Unsubscribe: - Add `RFC 2919`_ List-Id headers instead of modifying the subject :: List-Id: Example Mailing List Modern mail clients and webmail services generate unsubscribe buttons based on these headers. **Do not** * Remove or modify any existing headers from the original message, including From, Date, Subject, etc. * Add to or remove content from the message body, **including traditional disclaimers and unsubscribe footers** In addition to complying with DMARC, this configuration ensures that Reply and Reply All actions work like they would with any email message. Reply replies to the message sender, and Reply All replies to the sender and the list. Even without a subject prefix or body footer, mailing list users can still tell that a message came from the mailing list, because the message was sent to the mailing list post address, and not their email address. Configuration steps for common mailing list platforms are listed below. Mailman 2 ~~~~~~~~~ Navigate to General Settings, and configure the settings below ============================ ========== **Setting** **Value** **subject_prefix** **from_is_list** No **first_strip_reply_to** No **reply_goes_to_list** Poster **include_rfc2369_headers** Yes **include_list_post_header** Yes **include_sender_header** No ============================ ========== Navigate to Non-digest options, and configure the settings below =================== ========== **Setting** **Value** **msg_header** **msg_footer** **scrub_nondigest** No =================== ========== Navigate to Privacy Options> Sending Filters, and configure the settings below ====================================== ========== **Setting** **Value** **dmarc_moderation_action** Accept **dmarc_quarantine_moderation_action** Yes **dmarc_none_moderation_action** Yes ====================================== ========== Mailman 3 ~~~~~~~~~ Navigate to Settings> List Identity Make Subject prefix blank. Navigate to Settings> Alter Messages Configure the settings below ====================================== ========== **Setting** **Value** **Convert html to plaintext** No **Include RFC2369 headers** Yes **Include the list post header** Yes **Explicit reply-to address** **First strip replyto** No **Reply goes to list** No munging ====================================== ========== Navigate to Settings> DMARC Mitigation Configure the settings below ================================== =============================== **Setting** **Value** **DMARC mitigation action** No DMARC mitigations **DMARC mitigate unconditionally** No ================================== =============================== Create a blank footer template for your mailing list to remove the message footer. Unfortunately, the Postorius mailing list admin UI will not allow you to create an empty template, so you'll have to create one using the system's command line instead, for example: .. code-block:: bash touch var/templates/lists/list.example.com/en/list:member:regular:footer Where ``list.example.com`` the list ID, and ``en`` is the language. Then restart mailman core. Workarounds ----------- If a mailing list must go **against** best practices and modify the message (e.g. to add a required legal footer), the mailing list administrator must configure the list to replace the From address of the message (also known as munging) with the address of the mailing list, so they no longer spoof email addresses with domains protected by DMARC. Configuration steps for common mailing list platforms are listed below. Mailman 2 ~~~~~~~~~ Navigate to Privacy Options> Sending Filters, and configure the settings below ====================================== ========== **Setting** **Value** **dmarc_moderation_action** Munge From **dmarc_quarantine_moderation_action** Yes **dmarc_none_moderation_action** Yes ====================================== ========== .. note:: Message wrapping could be used as the DMARC mitigation action instead. In that case, the original message is added as an attachment to the mailing list message, but that could interfere with inbox searching, or mobile clients. On the other hand, replacing the From address might cause users to accidentally reply to the entire list, when they only intended to reply to the original sender. Choose the option that best fits your community. Mailman 3 ~~~~~~~~~ In the DMARC Mitigations tab of the Settings page, configure the settings below ================================== =============================== **Setting** **Value** **DMARC mitigation action** Replace From: with list address **DMARC mitigate unconditionally** No ================================== =============================== .. note:: Message wrapping could be used as the DMARC mitigation action instead. In that case, the original message is added as an attachment to the mailing list message, but that could interfere with inbox searching, or mobile clients. On the other hand, replacing the From address might cause users to accidentally reply to the entire list, when they only intended to reply to the original sender. LISTSERV ~~~~~~~~ `LISTSERV 16.0-2017a`_ and higher will rewrite the From header for domains that enforce with a DMARC quarantine or reject policy. Some additional steps are needed for Linux hosts. API === .. automodule:: parsedmarc :members: parsedmarc.elastic ------------------ .. automodule:: parsedmarc.elastic :members: .. toctree:: :maxdepth: 2 :caption: Contents: parsedmarc.splunk ----------------- .. automodule:: parsedmarc.splunk :members: .. toctree:: :maxdepth: 2 :caption: Contents: parsedmarc.utils ---------------- .. automodule:: parsedmarc.utils :members: .. toctree:: :maxdepth: 2 :caption: Contents: Indices and tables ================== * :ref:`genindex` * :ref:`modindex` * :ref:`search` .. |Build Status| image:: https://github.com/domainaware/parsedmarc/actions/workflows/python-tests.yml/badge.svg :target: https://github.com/domainaware/parsedmarc/actions/workflows/python-tests.yml .. |Code Coverage| image:: https://codecov.io/gh/domainaware/parsedmarc/branch/master/graph/badge.svg :target: https://codecov.io/gh/domainaware/parsedmarc .. |PyPI Package| image:: https://img.shields.io/pypi/v/parsedmarc.svg :target: https://pypi.org/project/parsedmarc/ .. _issues: https://github.com/domainaware/parsedmarc/issues .. _contributors: https://github.com/domainaware/parsedmarc/graphs/contributors .. _Demystifying DMARC: https://seanthegeek.net/459/demystifying-dmarc/ .. _IP to Country Lite database: https://db-ip.com/db/download/ip-to-country-lite .. _Creative Commons Attribution 4.0 International License: https://creativecommons.org/licenses/by/4.0/ .. _MaxMind GeoLite2 Country database: https://dev.maxmind.com/geoip/geolite2-free-geolocation-data .. _geoipupdate: https://github.com/maxmind/geoipupdate .. _Cloudflare's public resolvers: https://1.1.1.1/ .. _URL encoded: https://en.wikipedia.org/wiki/Percent-encoding#Percent-encoding_reserved_characters .. _Modern Auth/multi-factor authentication: http://davmail.sourceforge.net/faq.html .. _to comply with various privacy regulations: https://blog.maxmind.com/2019/12/18/significant-changes-to-accessing-and-using-geolite2-databases/ .. _registering for a free GeoLite2 account: https://www.maxmind.com/en/geolite2/signup .. _License Keys: https://www.maxmind.com/en/accounts/current/license-key .. _MaxMind geoipupdate page: https://dev.maxmind.com/geoip/geoipupdate/ .. _geoipupdate releases page on GitHub: https://github.com/maxmind/geoipupdate/releases .. _pypy3: https://www.pypy.org/download.html .. _Elasticsearch: https://www.elastic.co/guide/en/elasticsearch/reference/current/rpm.html .. _Kibana: https://www.elastic.co/guide/en/kibana/current/rpm.html .. _X-Pack: https://www.elastic.co/products/x-pack .. _ReadonlyREST: https://readonlyrest.com/ .. _export.ndjson: https://raw.githubusercontent.com/domainaware/parsedmarc/master/kibana/export.ndjson .. _HTTP Event collector (HEC): http://docs.splunk.com/Documentation/Splunk/latest/Data/AboutHEC .. _XML files: https://github.com/domainaware/parsedmarc/tree/master/splunk .. _Joe Nelson: https://begriffs.com/posts/2018-09-18-dmarc-mailing-list.html .. _RFC 2369: https://tools.ietf.org/html/rfc2369 .. _RFC 2919: https://tools.ietf.org/html/rfc2919 .. _LISTSERV 16.0-2017a: https://www.lsoft.com/news/dmarc-issue1-2018.asp