Sendmail Open Source
Open source subset of Sendmail Sentrion for enterprise email environments.
Sendmail Open Source is the open-source subset of Proofpoint's Sendmail Sentrion platform, designed for large and complex mail environments. The current Open Source release is Sendmail 8.16.1, distributed as a tar.gz archive with a PGP signature, and signed by the 2025 signing key. OpenDKIM is referenced as part of the Open Source offering.
Key Features
- Open Source subset of Sendmail Sentrion for enterprise-scale environments.
- Release 8.16.1 available on ftp.sendmail.org as a tar.gz archive with a PGP signature; signatures generated with the 2025 signing key.
- Includes OpenDKIM integration (DKIM) to authenticate messages.
- Security and licensing guidance, including CERT contact points and PGP signing keys.
Use Cases
- Deployments in large, complex mail infrastructures needing a durable open-source MTA with long-term manageability (virtualization, consolidation, cloud migration).
- Environments requiring verifiable, signed open-source builds from ftp.sendmail.org for audits and compliance.
- Setups needing DKIM-based mail signing and authentication controls.
Limitations and Considerations
- The Open Source option is a subset of the full Sendmail Sentrion offering; some enterprise features may be unavailable. Consult a specialist to assess fit.
Conclusion
Sendmail Open Source provides an officially supported open-source path for enterprise-style email deployments within the Sendmail Sentrion lineage. It offers a current release (8.16.1) with signed distributions and OpenDKIM support, suited for organizations able to manage an open-source MTA stack.
Categories:
Tags:
Tech Stack:
CSimilar Services
docker-mailserver
Containerized mail server stack for SMTP and IMAP with anti-spam
Production-ready mail server stack in a Docker container with SMTP, IMAP/POP3, LDAP auth, anti-spam/AV, DKIM/DMARC, and optional OAuth2 support.
Postal
Open source mail delivery platform for inbound and outbound email
Postal is an open source mail delivery platform for sending and receiving email, with SMTP support, web-based management, and tools for running your own SendGrid-style se...
Mail-in-a-Box
Turnkey email server with webmail, DNS, TLS, and admin panel
Mail-in-a-Box is a one-click mail server appliance for Ubuntu, bundling SMTP/IMAP, webmail, DNS, TLS automation, backups, and an admin control panel.
mailcow: dockerized
Docker-based email server suite with a web admin interface
Mailcow is a dockerized mail server suite providing SMTP/IMAP, webmail, anti-spam/anti-virus, and domain/mailbox administration via a unified web UI.
Stalwart Mail Server
All-in-one mail and collaboration server for modern and legacy protocols
All-in-one open-source mail and collaboration server with SMTP, IMAP, JMAP, CalDAV, CardDAV, and WebDAV, plus integrated anti-spam and phishing protection.
Mailu
Docker-based mail server with webmail and admin interface
Mailu is a full-featured mail server distributed as Docker images, providing SMTP/IMAP/POP3, webmail, administration UI, and built-in security and anti-spam features.