SMTP, Simple Mail Transfer Protocol, is a networking protocol for sending e-mail.
SMTP and Message Format
- RFC 5321 — Simple Mail Transfer Protocol (October 2008)
- RFC 5322 — Internet Message Format (October 2008)
RFC 6854 — Update to Internet Message Format to Allow Group Syntax in
Sender:Header Fields (March 2013)
- RFC 5336 — SMTP Extension for Internationalized Email Addresses (September 2008)