An email gateway is a type of solution that protects an organizations or users internal email servers. This solution acts as a gateway through which every incoming and outgoing email passes through. A Secure Email Gateway (SEG) is a device or software used for email monitoring that are being sent and received. Email gateway protection is designed to prevent unwanted email and deliver good email. Messages that are unwanted include spam, phishing attacks, malware or fraudulent content. Outgoing messages can be analyzed to prevent sensitive data from leaving the organization or to automatically encrypt emails that contain sensitive information. SEG functionality can be deployed as a cloud service, or as an on-premises appliance, depending on requirements.

A secure email gateway is essential to protecting your business from malicious content contained within emails by preventing them from reaching their intended recipient. By placing malicious emails into quarantine or blocking the sender, a secure email gateway significantly reduces the number of successful compromises of user credentials, email hosts and sensitive company data.

SEGs are designed to work in two main ways. They attempt to validate an email’s sender through domain authentication and sender reputation. And they try to validate its content using threat intelligence, antivirus, and content analysis tools.