RFC 3848 (rfc3848) - Page 1 of 4

ESMTP and LMTP Transmission Types Registration

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Network Working Group                                          C. Newman
Request for Comments: 3848                              Sun Microsystems
Category: Standards Track                                      July 2004


            ESMTP and LMTP Transmission Types Registration

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 (2004).

Abstract

   This registers seven new mail transmission types (ESMTPA, ESMTPS,
   ESMTPSA, LMTP, LMTPA, LMTPS, LMTPSA) for use in the "with" clause of
   a Received header in an Internet message.

1.  IANA Considerations

   As directed by SMTP [2], IANA maintains a registry [7] of "WITH
   protocol types" for use in the "with" clause of the Received header
   in an Internet message.  This registry presently includes SMTP [6],
   and ESMTP [2].  This specification updates the registry as follows:

   o  The new keyword "ESMTPA" indicates the use of ESMTP when the SMTP
      AUTH [3] extension is also used and authentication is successfully
      achieved.

   o  The new keyword "ESMTPS" indicates the use of ESMTP when STARTTLS
      [1] is also successfully negotiated to provide a strong transport
      encryption layer.

   o  The new keyword "ESMTPSA" indicates the use of ESMTP when both
      STARTTLS and SMTP AUTH are successfully negotiated (the
      combination of ESMTPS and ESMTPA).

   o  The new keyword "LMTP" indicates the use of LMTP [4].






Newman                      Standards Track
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