Meaning – The term mail gateway, refers to a machine that connects two or more electronic mail systems (often, mail systems on different networks) and transfers messages between them.
An email gateway is a type of email server that protects an organization’s or users’ internal email servers. This server acts as a gateway through which every incoming and outgoing email passes. A Secure Email Gateway (SEG) is a device or software used for email monitoring that is being sent and received. An SEG is designed to prevent unwanted emails and deliver good emails.
Example of usage – “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.”