Hornetsecurity VS MailScanner

Proofpoint - Proofpoint provides cloud-based email security, e-discovery and compliance solutions for companies to protect sensitive business data.

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

Mimecast Gateway - Mimecast Gateway is a SaaS-based email security solution that uses sophisticated, multi-layered detection engines and intelligence to protect email data and employees from malware, spam, advanced threats and zero-day attacks.

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

SpamTitan - Comprehensive Email Protection. 99.99% Spam Detection. Blocks phishing, viruses, malware and other email threats.

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