Sendmail Sentrion Open Source - Open Source Email Server | Proofpoint US | WarmIndex

Sendmail Sentrion Open Source is an enterprise-grade open-source email server for large, complex environments, offering DKIM authentication to protect against email fraud and ensure message integrity.

🚀 Overview

Sendmail Sentrion Open Source is a powerful, scalable open-source Mail Transfer Agent (MTA) derived from Proofpoint's commercial Sentrion platform. It delivers enterprise-level email handling capabilities tailored for demanding production environments.

What problem does this project solve? It addresses the challenges of managing high-volume, complex email infrastructures, including virtualization, server consolidation, and cloud migrations, while providing robust security through DKIM signing and verification to combat fraud and spoofing.

Who is it built for? Large organizations and sysadmins needing a reliable open-source email server with long-term support and enterprise scalability.

Why did you build it? Proofpoint released a subset of their proven Sentrion platform as open source to empower the community with production-ready tools, bridging open-source simplicity with enterprise reliability.

✨ Key Features

DKIM digital signing of messages to verify origin and integrity, crucial for preventing phishing and email fraud.
Cryptography-based sender authentication that safeguards organizational brand and reputation.
Scalable design optimized for large-scale deployments, supporting virtualization, consolidation, and cloud transitions.
Optional: PGP-signed releases and integration with OpenDKIM for advanced filtering.

🛠 Tech Stack

Backend: Sendmail platform (version 8.18.2), OpenDKIM (forked from dkim-milter 2.8.3)
Language: C libraries for DKIM-aware applications and milters
Security: PGP/GPG for release signing
Deployment: Self-hosted on Linux/Unix systems