Email security gateway is a software or hardware solution that is used to protect email communications from malicious or unwanted emails, such as spam, phishing, and malware. Email security gateways typically use a combination of techniques such as filtering, encryption, and authentication to protect email communications. They may also include features such as data loss prevention (DLP) and archiving. It is located between an organization's email server and the internet, and filters incoming and outgoing email traffic to identify and block potentially harmful messages.