This memo describes a low cost, deterministic means for messages to be identified as submissions, and specifies what actions are to be taken by a submission server. [STANDARDS-TRACK]| IETF Datatracker
This memo defines an extension to the SMTP service [RFC-821, RFC-1869] whereby an SMTP server augments its responses with the enhanced mail system status codes defined in RFC 1893. [STANDARDS-TRACK]| IETF Datatracker
This document describes an extension to the SMTP (Simple Mail Transfer Protocol) service that allows an SMTP server and client to use TLS (Transport Layer Security) to provide private, authenticated communication over the Internet. This gives SMTP agents the ability to protect some or all of their communications from eavesdroppers and attackers. [STANDARDS-TRACK]| IETF Datatracker