Next-Generation Intrusion Prevention System (NGIPS) - Cisco Firepower NGIPS (Next-Generation IPS) provides contextual awareness, security intelligence, and advanced threat protection against attacks and malware.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
snort - Snort is a free and open source network intrusion prevention system.
SpamAssassin - Use this program to "Unspam" your mailbox(es).
Suricata - Suricata is a high performance Network IDS, IPS and Network Security Monitoring engine.
Proxmox Mail Gateway - Protect mail server against spam, viruses and malware with Proxmox Mail Gateway security for businesses, government, education and non-profit organizations.