Barracuda Email Security Service VS SonicWALL Email Security Series Appliances

Trustwave Secure Email Gateway - Trustwave Secure Email Gateway helps protect your email environment against modern threats such as malware, ransomware and phishing, and helps prevent loss of sensitive corporate data.

Mimecast Secure Email Gateway - Prevent targeted email-borne attacks with Mimecast Secure Email Gateway for cloud-based anti-virus and anti-spam protection.

FortiMail - Fortinet Email security is designed to block ransomware, phishing, and other cyber threats seeking entry via incoming email and outgoing messages don’t improperly leak sensitive data.

Appriver - AppRiver is an email and web security company, develops SaaS-based anti-spam, hosted exchange, email encryption and web protection solutions.

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

Microsoft Exchange - Secure Email Gateway