SMTP (or Simple Mail Transfer Protocol), is a protocol for sending email messages between servers. Most email systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an email client using an email download protocol (usually either POP3 or IMAP).
In addition, SMTP is generally used to send messages from a mail client to a mail server. This is why you need to specify both the incoming mail (POP3 or IMAP) server and the SMTP server when you configure your email application.
SMTP now operates on port 587. The ports 25 and 465 are no longer supported. Our SMTP servers require authentication via SMTP AUTH, supporting the secure SSL/TLS.
We recommend using STARTTLS encryption.