TCP port 465 for SSL encrypted traffic (SMTPS).This protocol belongs to the application level of the TCP / IP model, uses the TCP transport layer protocol, and makes use of different ports depending on whether the traffic is encrypted or not: This protocol is used by local email clients to send email messages to the remote mail server, therefore, it acts only in the outbound direction, unlike the POP3 protocol that is used to receive emails, this SMTP is used to send them. The SMTP protocol (Simple Mail Transfer Protocol) or also known as “Simple Mail Transfer Protocol” is the protocol used when we are going to send an email through a mail server.