SMTP
The menu Email Protection > SMTP allows you to configure the SMTP proxy. SMTP is the abbreviation of Simple Mail Transfer Protocol, a protocol used to deliver emails to a mail server. Sophos UTM includes an application level gateway for SMTP, which can be used to protect your internal mail server from remote attacks and additionally provides powerful virus scanning and email filtering services.
Note – To use the SMTP proxy correctly, a valid name server (DNS) must be configured.