AKAYLA

Mountain View CA 94043 United States of America peter@akayla.com

sec ssh iana registry This specification updates the registration policies for adding new entries to registries within the IANA "Secure Shell (SSH) Protocol Parameters" group of registries. Previously, the registration policy was generally IETF Review, as defined in RFC 8126, although a few registries require Standards Action. This specification changes it from IETF Review to Expert Review. This document updates RFCs 4250, 4716, 4819, and 8308.

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 .

Copyright Notice Copyright (c) 2024 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 () 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.

Table of Contents

• .  Introduction
  • .  Requirements Language
• .  SSH Protocol Parameters Affected
• .  Designated Expert Pool
• .  IANA Considerations
• .  Security Considerations
• .  References
  • .  Normative References
  • .  Informative References
• Acknowledgements
• Author's Address

Introduction The IANA "Secure Shell (SSH) Protocol Parameters" registry was populated by several RFCs including , , , and . Outside of some narrow value ranges that require Standards Action in order to add new values or that are marked for Private Use, the registration policy for other portions of the registry was IETF Review . This specification changes the policy from IETF Review to Expert Review. This change is in line with similar changes undertaken for certain IPsec and TLS registries.

Requirements Language 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 when, and only when, they appear in all capitals, as shown here.

SSH Protocol Parameters Affected The following table lists the "Secure Shell (SSH) Protocol Parameters" registries whose registration policy has changed from IETF Review to Expert Review. Where this change applied to a specific range of values within the particular parameter, that range is given in the notes column. Affected registries now list this document as a reference. Secure Shell (SSH) Protocol Parameters Affected

Parameter Name	RFC	Notes
Authentication Method Names
Channel Connection Failure Reason Codes and Descriptions		0x00000001-0xFDFFFFFF (inclusive)
Compression Algorithm Names
Connection Protocol Channel Request Names
Connection Protocol Channel Types
Connection Protocol Global Request Names
Connection Protocol Subsystem Names
Disconnection Messages Reason Codes and Descriptions		0x00000001-0xFDFFFFFF (inclusive)
Encryption Algorithm Names
Extended Channel Data Transfer data_type_code and Data		0x00000001-0xFDFFFFFF (inclusive)
Extension Names
Key Exchange Method Names
MAC Algorithm Names
Pseudo-Terminal Encoded Terminal Modes
Public Key Algorithm Names
Publickey Subsystem Attributes
Publickey Subsystem Request Names
Publickey Subsystem Response Names
Service Names
Signal Names
SSH Public-Key File Header Tags		Excluding header-tags beginning with x-

The only IANA SSH protocol parameter registries not affected are "Message Numbers" and "Publickey Subsystem Status Codes", as these remain Standards Action due to their limited resources as one-byte registry values.

Designated Expert Pool Expert Review registry requests are registered after a three-week review period on the <ssh-reg-review@ietf.org> mailing list, and on the advice of one or more designated experts. However, to allow for the allocation of values prior to publication, the designated experts may approve registration once they are satisfied that such a specification will be published. Registration requests sent to the mailing list for review SHOULD use an appropriate subject (e.g., "Request to register value in SSH protocol parameters <specific parameter> registry"). Within the review period, the designated experts will either approve or deny the registration request, communicating this decision to the review list and IANA. Denials MUST include an explanation and, if applicable, suggestions as to how to make the request successful. Registration requests that are undetermined for a period longer than 21 days can be brought to the IESG's attention (using the <iesg@ietf.org> mailing list) for resolution. Criteria that SHOULD be applied by the designated experts includes determining whether the proposed registration duplicates existing functionality (which is not permitted), whether it is likely to be of general applicability or useful only for a single application, and whether the registration description is clear. IANA MUST only accept registry updates from the designated experts and the IESG. It SHOULD direct all requests for registration from other sources to the review mailing list. It is suggested that multiple designated experts be appointed who are able to represent the perspectives of different applications using this specification, in order to enable broadly informed review of registration decisions. In cases where a registration decision could be perceived as creating a conflict of interest for a particular expert, that expert SHOULD defer to the judgment of the other experts.

IANA Considerations This memo is entirely about updating the IANA "Secure Shell (SSH) Protocol Parameters" registry.

Security Considerations This memo does not change the Security Considerations for any of the updated RFCs.

References Normative References In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document defines the instructions to the IANA and the initial state of the IANA assigned numbers for the Secure Shell (SSH) protocol. It is intended only for the initialization of the IANA registries referenced in the set of SSH documents. [STANDARDS-TRACK] Secure Shell defines a user authentication mechanism that is based on public keys, but does not define any mechanism for key distribution. No common key management solution exists in current implementations. This document describes a protocol that can be used to configure public keys in an implementation-independent fashion, allowing client software to take on the burden of this configuration. The Public Key Subsystem provides a server-independent mechanism for clients to add public keys, remove public keys, and list the current public keys known by the server. Rights to manage public keys are specific and limited to the authenticated user. A public key may also be associated with various restrictions, including a mandatory command or subsystem. [STANDARDS-TRACK] Many protocols make use of points of extensibility that use constants to identify various protocol parameters. To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper. For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA). To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed. This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry. This is the third edition of this document; it obsoletes RFC 5226. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This memo updates RFCs 4251, 4252, 4253, and 4254 by defining a mechanism for Secure Shell (SSH) clients and servers to exchange information about supported protocol extensions confidentially after SSH key exchange. Informative References message to the Curdle mailing list This document formally documents an existing public key file format in use for exchanging public keys between different Secure Shell (SSH) implementations. In addition, this document defines a standard textual representation for SSH public key fingerprints. This memo provides information for the Internet community.

Acknowledgements The impetus for this specification was a February 2021 discussion on the CURDLE mailing list .

Author's Address AKAYLA

Mountain View CA 94043 United States of America peter@akayla.com