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SMTP Require TLS Option

Document Type Replaced Internet-Draft (individual)
Expired & archived
Author Jim Fenton
Last updated 2017-08-17 (Latest revision 2017-02-13)
Replaced by RFC 8689
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Replaced by draft-ietf-uta-smtp-require-tls
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


The SMTP STARTTLS option, used in negotiating transport-level encryption of SMTP connections, is not as useful from a security standpoint as it might be because of its opportunistic nature; message delivery is prioritized over security. This document describes a complementary SMTP service extension, REQUIRETLS. If the REQUIRETLS option is used when sending a message, it asserts a request on the part of the message sender to override the default negotiation of TLS, either by requiring that TLS be negotiated when the message is relayed, or by requesting that policy mechanisms such as SMTP STS and DANE be ignored when relaying a high priority message.


Jim Fenton

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)