Vendors.

High-performance open-source spam filtering with Bayesian learning, fuzzy hashing, and neural network support. Compare Rspamd with other email security tools.

Open-source anti-spam platform providing email filtering using heuristic analysis, Bayesian filtering, and DNS blocklists

Open-source email archiving with full-text search, retention policies, and audit-ready compliance tools. Compare Piler for MSP email management.

Open source email security system for Linux-based email gateways protecting against viruses, spam, phishing, and malware

Open-source email filtering framework that works with Sendmail's Milter API to provide customizable mail filtering in Perl.

High-performance interface between mailer (MTA) and content checkers like spam and antivirus scanners

Cloud-based email security for SMBs with advanced threat protection, URL defense, and email continuity. Review Proofpoint Essentials for MSP clients.

Comprehensive email security solution protecting against spam, malware, and advanced threats with AI-powered detection.

Cloud-based advanced email security platform protecting against sophisticated email attacks, malware, and data loss.

Open-source email gateway with spam filtering, virus scanning, and policy-based routing to protect mail infrastructure. Review Proxmox Mail Gateway.