EMailFilter

EMailFilter is an open-source email filtering engine designed to classify, route, and enforce policies on email traffic. It can be deployed as a gateway between mail transfer agents and mail servers, and supports inbound and outbound processing.

Key features include both rule-based and machine-learning classification, DKIM/SPF/DMARC checks, antivirus and anti-malware integration, attachment scanning, URL reputation analysis, and integration with external threat intelligence feeds. It supports quarantine, tagging, delivery, or rejection actions, and provides detailed logs and audit trails. The system is extensible via plugins and exposes a REST API and an administrative UI.

Architecture: modular design with components such as ingestion, classification, policy enforcement, enrichment, storage, and API services. It can work as a gateway in MTA configurations and integrates with common mail servers such as Postfix, Exim, and Sendmail through standard interfaces like LMTP or MDA.

Deployment and support: available as on-premises software and as containerized deployments with Docker and orchestrators. It supports high-availability setups, incremental updates, and scalable processing for larger mail flows. Platform support is primarily Linux-based, with planned or limited support for other environments depending on release.

Licensing and governance: EMailFilter is maintained by an open-source community. The project is distributed under an open-source license, with governance and contribution guidelines provided in the project repository. Documentation covers installation, configuration, troubleshooting, and best practices.

See also: email filtering, spam filter, phishing protection.