What are some alternatives?
EuropeanMX - Protects your company by blocking spam and virus before they reach your network.
Symantec Email Security.cloud - Symantec Email Security.cloud provides always-on, inbound and outbound email security against malware, targeted attacks, and advanced threats
Barracuda - Barracuda Networks offers industry-leading network security products for data storage & disaster recovery, content security, and networking & application delivery.
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.
Hornetsecurity - Hornetsecurity offers you comprehensive, integrated managed e-mail security services.
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.