Network Working Group A. Melnikov
Internet-Draft Isode Ltd
Intended status: Standards Track 21 February 2025
Expires: 25 August 2025
Updates to SMTP related IANA registries
draft-melnikov-smtp-iana-cleanup-00
Abstract
While EMAILCORE working group was working on update to SMTP
specification, it became clear that existing SMTP related registries
need to be restructured and existing entries need to be updated.
This document describes these tasks.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 2
3.1. Updates to the "Simple Mail Transfer Protocol (SMTP)
Service Extensions" registry . . . . . . . . . . . . . . 2
3.1.1. Updates to the "References" field . . . . . . . . . . 3
3.1.2. Updates to the "EHLO Parameters" field . . . . . . . 3
3.1.3. Updates to the "Message submission Use and Values"
field . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1.4. Updates to the "Additional verbs", "MAIL/RCPT Parameter
Values" fields . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Normative References . . . . . . . . . . . . . . . . . . 5
5.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
While EMAILCORE working group was working on update to SMTP
specification [I-D.ietf-emailcore-rfc5321bis], it became clear that
existing SMTP related registries need to be restructured and some
existing entries need to be updated. This document describes these
tasks, assuming IANA actions specified in
[I-D.ietf-emailcore-rfc5321bis] were already performed.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. IANA Considerations
3.1. Updates to the "Simple Mail Transfer Protocol (SMTP) Service
Extensions" registry
Updates to the "Simple Mail Transfer Protocol (SMTP) Service
Extensions" registry are described as an ordered list of steps that
should be performed sequentually. Each step is described by a
subsection of this section.
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3.1.1. Updates to the "References" field
IANA is requested to change values of the "References" field for
"EXPN" and "HELP" extensions to [I-D.ietf-emailcore-rfc5321bis]. The
"References" field values for "SEND", "SOML", "SAML" and "TURN"
remain unchanged, as they were obsoleted and there are no newer
reference than RFC 821.
3.1.2. Updates to the "EHLO Parameters" field
IANA is requested to update the following values in this field:
1. The value corresponding to the DELIVERBY extension should be
changed to "A comma separated list of options (optional)".
2. The value corresponding to the FUTURERELEASE extension should be
changed to "max-future-release-interval and max-future-release-
date-time".
3. The value corresponding to the LIMITS extension should be changed
to "List of limits".
3.1.3. Updates to the "Message submission Use and Values" field
IANA is requested to update values corresponding to "HELP", "BURL",
"FUTURERELEASE", "SMTPUTF8", "MT-PRIORITY", "RRVS", "REQUIRETLS" and
"LIMITS" extensions to "MAY".
3.1.4. Updates to the "Additional verbs", "MAIL/RCPT Parameter Values"
fields
IANA is requested to update "Additional verbs" and "MAIL/RCPT
Parameter Values" fields as per the table specified below:
+=====================+============+================================+
| EHLO Keyword | Additional | MAIL/RCPT Parameter Values |
| | verbs | |
+=====================+============+================================+
| SEND | SEND | none |
+---------------------+------------+--------------------------------+
| SOML | SOML | none |
+---------------------+------------+--------------------------------+
| SAML | SAML | none |
+---------------------+------------+--------------------------------+
| EXPN | EXPN | none |
+---------------------+------------+--------------------------------+
| HELP | HELP | none |
+---------------------+------------+--------------------------------+
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| TURN | TURN | none |
+---------------------+------------+--------------------------------+
| 8BITMIME | none | BODY parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
| SIZE | none | SIZE parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
| CHUNKING | BDAT | none |
+---------------------+------------+--------------------------------+
| BINARYMIME | none | BODY parameter to MAIL |
| | | command (an extra choice |
| | | was added) |
+---------------------+------------+--------------------------------+
| CHECKPOINT | none | TRANSID parameter to the |
| | | MAIL command |
+---------------------+------------+--------------------------------+
| DELIVERBY | none | BY parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
| PIPELINING | none | none |
+---------------------+------------+--------------------------------+
| DSN | none | NOTIFY and ORCPT |
| | | parameters to RCPT |
| | | command. RET and ENVID |
| | | parameters to MAIL command |
+---------------------+------------+--------------------------------+
| ETRN | ETRN | none |
+---------------------+------------+--------------------------------+
| ENHANCEDSTATUSCODES | none | none |
+---------------------+------------+--------------------------------+
| STARTTLS | STARTTLS | none |
+---------------------+------------+--------------------------------+
| NO-SOLICITING | none | SOLICIT parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
| MTRK | none | MTRK parameters to MAIL |
| | | command. Also see DSN |
| | | extension parameters |
+---------------------+------------+--------------------------------+
| SUBMITTER | none | SUBMITTER parameters to |
| | | MAIL command |
+---------------------+------------+--------------------------------+
| ATRN | ATRN | none |
+---------------------+------------+--------------------------------+
| AUTH | AUTH | AUTH parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
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| BURL | BURL | none |
+---------------------+------------+--------------------------------+
| FUTURERELEASE | none | HOLDFOR and HOLDUNTIL |
| | | parameters to MAIL |
| | | command. |
+---------------------+------------+--------------------------------+
| UTF8SMTP | none | One optional parameter, |
| | | ALT-ADDRESS, is added to |
| | | the MAIL and RCPT commands |
+---------------------+------------+--------------------------------+
| CONPERM | none | CONPERM parameter to MAIL |
| | | command |
+---------------------+------------+--------------------------------+
| CONNEG | none | CONNEG parameter to RCPT |
| | | command |
+---------------------+------------+--------------------------------+
| SMTPUTF8 | none | SMTPUTF8 parameter to the |
| | | MAIL command |
+---------------------+------------+--------------------------------+
| MT-PRIORITY | none | MT-PRIORITY parameter to |
| | | MAIL command |
+---------------------+------------+--------------------------------+
| RRVS | none | RRVS parameter to RCPT |
| | | command |
+---------------------+------------+--------------------------------+
| REQUIRETLS | none | REQUIRETLS parameter to |
| | | MAIL command |
+---------------------+------------+--------------------------------+
| LIMITS | none | none |
+---------------------+------------+--------------------------------+
Table 1
TBD: Add and/or calculate "Length Added" values.
4. Security Considerations
This document only specifies IANA related actions, thus it doesn't
directly affect security on SMTP or its extensions. However better
documentation of SMTP extensions in IANA registries can, hopefully,
lead to better and more secure implementations.
5. References
5.1. Normative References
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[I-D.ietf-emailcore-rfc5321bis]
Klensin, J. C., "Simple Mail Transfer Protocol", Work in
Progress, Internet-Draft, draft-ietf-emailcore-rfc5321bis-
40, 3 February 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-
emailcore-rfc5321bis-40>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
5.2. Informative References
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<https://www.rfc-editor.org/info/rfc5321>.
Author's Address
Alexey Melnikov
Isode Ltd
14 Castle Mews
Hampton
TW12 2NP
United Kingdom
Email: alexey.melnikov@isode.com
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