Rspamd
Open source spam and phishing filtering system for Postfix, Exim, and Sendmail.
Technical Architecture & Overview
Rspamd is a filtering system written in C with Lua extension support. It evaluates messages through SPF, DKIM, DMARC, and ARC checks, DNS blocklists, greylisting, statistical classifiers, and content rules, then applies a combined score. The project reports eighteen years in production, and the engine integrates with major MTAs through milter or native protocols. Optional commercial plans exist alongside the open source core.
Targeted Technical Use Cases
Self-hosted mail platforms that need a maintained filtering engine with tunable scoring.
Evaluation & Trade-offs
Core Strengths
- +The project states it scans hundreds of messages per second per core.
- +Extensible rule and plugin system in Lua.
- +SPF, DKIM, DMARC, and ARC validation built in.
Trade-Offs & Limitations
- -Requires operating the surrounding mail infrastructure.
- -Tuning symbol scores takes experience.
Defensive Security Application
Filtering inbound mail for self-hosted domains without routing mail through a third-party gateway.
Frequently Asked Questions
What is Rspamd?→
Rspamd is a filtering system written in C with Lua extension support. It evaluates messages through SPF, DKIM, DMARC, and ARC checks, DNS blocklists, greylisting, statistical classifiers, and content rules, then applies a combined score. The project reports eighteen years in production, and the engine integrates with major MTAs through milter or native protocols. Optional commercial plans exist alongside the open source core.
What is Rspamd used for?→
Self-hosted mail platforms that need a maintained filtering engine with tunable scoring.
What are the strengths of Rspamd?→
- +The project states it scans hundreds of messages per second per core.
- +Extensible rule and plugin system in Lua.
- +SPF, DKIM, DMARC, and ARC validation built in.
What are the limitations of Rspamd?→
- +Requires operating the surrounding mail infrastructure.
- +Tuning symbol scores takes experience.
How is Rspamd used defensively?→
Filtering inbound mail for self-hosted domains without routing mail through a third-party gateway.