RFC 3207 (rfc3207) - Page 1 of 9

SMTP Service Extension for Secure SMTP over Transport Layer Security

Network Working Group                                         P. Hoffman
Request for Comments: 3207                      Internet Mail Consortium
Obsoletes: 2487                                            February 2002
Category: Standards Track


                      SMTP Service Extension for
               Secure SMTP over Transport Layer Security

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   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.

1. Introduction

   SMTP [RFC 2821] servers and clients normally communicate in the clear
   over the Internet.  In many cases, this communication goes through
   one or more router that is not controlled or trusted by either
   entity.  Such an untrusted router might allow a third party to
   monitor or alter the communications between the server and client.

   Further, there is often a desire for two SMTP agents to be able to
   authenticate each others' identities.  For example, a secure SMTP
   server might only allow communications from other SMTP agents it
   knows, or it might act differently for messages received from an
   agent it knows than from one it doesn't know.








Hoffman                     Standards Track