Maldun Email Security Gateway (ESG) is a multi-featured mail gateway that provides inbound and outbound email security, as well as other functions. It has the capability to filter out all sorts of email threats like spam, virus, phishing/scam, marketing/graymail, and other unwanted email messages. It has eight tiers of protection, including connection control and authentication, adaptive sender reputation filtering, anti-virus filtering, anti-spam protection, graymail detection, advanced threat protection, anomaly detection, and content filters.