SMTP is the Simple Mail Transfer Protocol.
SMTP stands for the Simple Mail Transfer Protocol, used to send electronic mail from your computer through an SMTP server, which is usually operated by your Internet service provider or network administrator. When configuring or troubleshooting Internet email, SMTP may also be referred to as "outgoing email" or "sending email."
SMTP is an industry standard protocol that allows different companies' products to work together.
The SMTP protocol is described in depth in RFC document number 821 (http://www.ietf.org/rfc/rfc0821.txt).
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