SpamExperts - SpamExperts applies its proprietary smart technologies to eliminate spam, virus and malware mail before it reaches your network.

Proxmox Mail Gateway - Protect mail server against spam, viruses and malware with Proxmox Mail Gateway security for businesses, government, education and non-profit organizations.

SpamHero - SpamHero is a professional spam filtering accuracy while lowering the cost to domain and business owners.

SpamAssassin - Use this program to "Unspam" your mailbox(es).

Mimecast - Utilities, Application Utilities, and Security

Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...