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

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

Datatune Spam Filtering - Datatune's hosted antispam solution is a cloud-based email security tool.

Mimecast - Utilities, Application Utilities, and Security

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

SpamExperts Outgoing Filter - The outbound email filtering prevents spam from being unknowingly sent out of your network through a compromised account or script.