Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and Access
RFC 8314
Document | Type | RFC - Proposed Standard (January 2018; Errata) | |
---|---|---|---|
Authors | Keith Moore , Chris Newman | ||
Last updated | 2018-04-16 | ||
Replaces | draft-newman-email-deep | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Leif Johansson | ||
Shepherd write-up | Show (last changed 2017-09-29) | ||
IESG | IESG state | RFC 8314 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Alexey Melnikov | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) K. Moore Request for Comments: 8314 Windrock, Inc. Updates: 1939, 2595, 3501, 5068, 6186, 6409 C. Newman Category: Standards Track Oracle ISSN: 2070-1721 January 2018 Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and Access Abstract This specification outlines current recommendations for the use of Transport Layer Security (TLS) to provide confidentiality of email traffic between a Mail User Agent (MUA) and a Mail Submission Server or Mail Access Server. This document updates RFCs 1939, 2595, 3501, 5068, 6186, and 6409. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8314. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Moore & Newman Standards Track [Page 1] RFC 8314 Use of TLS for Email Submission/Access January 2018 Table of Contents 1. Introduction ....................................................3 1.1. How This Document Updates Previous RFCs ....................3 2. Conventions and Terminology Used in This Document ...............4 3. Implicit TLS ....................................................5 3.1. Implicit TLS for POP .......................................5 3.2. Implicit TLS for IMAP ......................................5 3.3. Implicit TLS for SMTP Submission ...........................6 3.4. Implicit TLS Connection Closure for POP, IMAP, and SMTP Submission ............................................7 4. Use of TLS by Mail Access Servers and Message Submission Servers .........................................................7 4.1. Deprecation of Services Using Cleartext and TLS Versions Less Than 1.1 ..............................................8 4.2. Mail Server Use of Client Certificate Authentication .......9 4.3. Recording TLS Ciphersuite in "Received" Header Field .......9 4.4. TLS Server Certificate Requirements .......................10 4.5. Recommended DNS Records for Mail Protocol Servers .........11 4.5.1. MX Records .........................................11 4.5.2. SRV Records ........................................11 4.5.3. DNSSEC .............................................11 4.5.4. TLSA Records .......................................11 4.6. Changes to Internet-Facing Servers ........................11 5. Use of TLS by Mail User Agents .................................12 5.1. Use of SRV Records in Establishing Configuration ..........13 5.2. Minimum Confidentiality Level .............................14 5.3. Certificate Validation ....................................15 5.4. Certificate Pinning .......................................15 5.5. Client Certificate Authentication .........................16 6. Considerations Related to Antivirus/Antispam Software and Services ...................................................17 7. IANA Considerations ............................................17 7.1. POP3S Port Registration Update ............................17 7.2. IMAPS Port Registration Update ............................18 7.3. Submissions Port Registration .............................18 7.4. Additional Registered Clauses for "Received" Fields .......19 8. Security Considerations ........................................19 9. References .....................................................20 9.1. Normative References ......................................20Show full document text