Barracuda Email Security Gateway - Barracuda's Email Security Gateway is a powerful antivirus filter specifically designed to identify and eliminate email-borne threats, stopping hazards before they reach the network.
TinyWall - Lightweight and non-intrusive firewall
Symantec Email Security.cloud - Symantec Email Security.cloud provides always-on, inbound and outbound email security against malware, targeted attacks, and advanced threats
SonicWall - SonicWall security solutions protects your network, systems, users and data from cyber threats.
Proofpoint Email Security and Protection - Learn about Proofpoint's email security solutions that protect organizations against threats such as email fraud, phishing, spam, bulk email, and viruses.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more