RFC 9456 | Updates to the TLSTM for SNMP | November 2023
Vaughn | Standards Track | [Page]

Stream:
  Internet Engineering Task Force (IETF)
RFC:
  9456
Updates:
  6353
Category:
  Standards Track
Published:
  November 2023
ISSN:
  2070-1721
Author:
  K. Vaughn, Ed.
  Trevilon LLC

# RFC 9456

# Updates to the TLS Transport Model for SNMP

## Abstract

This document updates RFC 6353 ("Transport Layer Security (TLS) Transport Model for the Simple Network Management Protocol (SNMP)") to reflect changes necessary to support Transport Layer Security version 1.3 (TLS 1.3) and Datagram Transport Layer Security version 1.3 (DTLS 1.3), which are jointly known as "(D)TLS 1.3". This document is compatible with (D)TLS 1.2 and is intended to be compatible with future versions of SNMP and (D)TLS.¶

This document updates the SNMP-TLS-TM-MIB as defined in RFC 6353.¶

## 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/rfc9456.¶

## Copyright Notice

Copyright (c) 2023 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 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.¶

## 1. Introduction

This document updates and clarifies how the rules of [RFC6353] apply when using Transport Layer Security (TLS) or Datagram Transport Layer Security (DTLS) versions later than 1.2. This document jointly refers to these two protocols as "(D)TLS". The update also emphasizes the requirement in [RFC8996] prohibiting the use of TLS versions prior to TLS 1.2 [RFC5246] when using SNMP. Although the text of this document specifically references SNMPv3 and (D)TLS 1.3, this document may be applicable to future versions of these protocols and is backwards compatible with (D)TLS 1.2.¶

### 1.1. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to Section 7 of [RFC3410].¶

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in RFCs 2578, 2579, and 2580 [STD58].¶

### 1.2. Conventions

Within this document, the terms "TLS", "DTLS", and "(D)TLS" apply to all versions of the indicated protocols. The term "SNMP" means "SNMPv3" unless a specific version number is indicated. Specific version numbers are used when the text needs to emphasize version numbers.¶

For consistency with SNMP-related specifications, this document favors terminology as defined in [STD62], rather than favoring terminology that is consistent with non-SNMP specifications. This is consistent with the IESG decision to not require that the SNMP terminology be modified to match the usage of other non-SNMP specifications when SNMP was advanced to an Internet Standard. "Authentication" in this document typically refers to the English meaning of "serving to prove the authenticity of" the message, not data source authentication or peer identity authentication. The terms "manager" and "agent" are not used in this document because, in the architecture defined in RFC 3411 [STD62], all SNMP entities have the capability of acting as manager, agent, or both, depending on the SNMP application types supported in the implementation. Where distinction is necessary, the application names of command generator, command responder, notification originator, notification receiver, and proxy forwarder are used. See "An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks" (RFC 3411 [STD62]) for further information.¶

Throughout this document, the terms "client" and "server" are used to refer to the two ends of the TLS transport connection. The client actively opens the TLS connection, and the server passively listens for the incoming TLS connection. An SNMP entity MAY act as a TLS client, TLS server, or both, depending on the SNMP applications supported.¶

Throughout this document, the term "session" is used to refer to a secure association between two instances of the TLS Transport Model (TLSTM) that permits the transmission of one or more SNMP messages within the lifetime of the session. The TLS protocol also has an internal notion of a session, and although these two concepts of a session are related, when the term "session" is used, this document is referring to the TLSTM's specific session and not directly to the TLS protocol's session.¶

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.¶

## 2. Changes from RFC 6353

This document updates [RFC6353]. The changes from [RFC6353] are defined in the following subsections.¶

### 2.1. TLSTM Fingerprint

[RFC6353] defines the SnmpTLSFingerprint textual convention to include the one-octet TLS 1.2 hash algorithm identifier. This one-octet algorithm identifier is only applicable to (D)TLS protocol versions prior to 1.3. The TLS community does not plan to ever add additional values to the "TLS HashAlgorithm" registry [RFC5246], because some might incorrectly infer that using a new hash algorithm with TLS 1.2 would overcome the limitations of TLS 1.2. However, there is still a need within TLSTM to support new values as they are developed.¶

This document updates the definition of SnmpTLSFingerprint to clarify that the one-octet algorithm identifier uses the values in the IANA "SNMP-TLSTM HashAlgorithms" registry; this registry is consistent with the IANA "TLS HashAlgorithm" registry for its initial values but can be extended as needed to support new hashing algorithms without implying that the new values can be used by TLS version 1.2. This change allows the reuse of the existing fingerprint textual convention and minimizes the impact to [RFC6353].¶

A "Y" in the "Recommended" column (Table 1) indicates that the registered value has been recommended through a formal Standards Action [RFC8126]. Not all parameters defined in Standards Track documents are necessarily marked as "Recommended".¶

An "N" in the "Recommended" column does not necessarily mean that the value is flawed; rather, it indicates that the item either has not been through the IETF consensus process, has limited applicability, or is intended only for specific use cases.¶

The initial values for the "SNMP-TLSTM HashAlgorithms" registry are defined below:¶

Table 1: SNMP-TLSTM Hash Algorithms
Value | Description | Recommended | References
--- | --- | --- | ---
0 | none | N | [RFC5246]
1 | md5 | N | [RFC5246]
2 | sha1 | N | [RFC5246]
3 | sha224 | Y | [RFC5246]
4 | sha256 | Y | [RFC5246]
5 | sha384 | Y | [RFC5246]
6 | sha512 | Y | [RFC5246]
7 | Reserved |  | [RFC8447]
8 | Intrinsic | N | [RFC8422]
9-223 | Unassigned |  |
224-255 | Reserved for Private Use |  | [RFC5246]

Values 0 through 2 MUST NOT be used by implementations of this document but are listed for historical consistency.¶

### 2.2. Security Level

The architecture defined in RFC 3411 [STD62] recognizes three levels of security:¶

- without authentication and without privacy (noAuthNoPriv)¶
- with authentication but without privacy (authNoPriv)¶
- with authentication and with privacy (authPriv)¶

Cipher suites for (D)TLS 1.3 defined in [RFC8446] provide both authentication and privacy. Cipher suites defined in [RFC9150] for (D)TLS 1.3 provide only authentication, without any privacy protection. Implementations MAY choose to force (D)TLS 1.3 to only allow cipher suites that provide both authentication and privacy.¶

### 2.3. (D)TLS Version

[RFC6353] states that TLSTM clients and servers MUST NOT request, offer, or use SSL 2.0. [RFC8996] prohibits the use of (D)TLS versions prior to version 1.2. TLSTM MUST only be used with (D)TLS versions 1.2 and later.¶

## 3. Additional Rules for TLS 1.3

This document specifies additional rules and clarifications for the use of TLS 1.3. These rules may additionally apply to future versions of TLS.¶

### 3.1. Zero Round-Trip Time Resumption (0-RTT)

TLS 1.3 implementations for SNMP MUST NOT enable the 0-RTT mode of session resumption (either sending or accepting) and MUST NOT automatically resend 0-RTT data if it is rejected by the server. 0-RTT is disallowed because there are no "safe" SNMP messages that, if replayed, will be guaranteed to cause no harm at the server side: all incoming notifications or command responses are meant to be acted upon only once. See Section 5 ("Security Considerations") for further details.¶

TLSTM clients and servers MUST NOT request, offer, or use the 0-RTT mode of TLS 1.3. [RFC8446] removed the renegotiation supported in TLS 1.2 [RFC5246]; for session resumption, it introduced a zero-RTT (0-RTT) mode, saving a round trip at connection setup at the cost of increased risk of replay attacks (it is possible for servers to guard against this attack by keeping track of all the messages received). [RFC8446] requires that a profile be written for any application that wants to use 0-RTT, specifying which messages are "safe to use" with this mode. Within SNMP, there are no messages that are "safe to use" with this mode.¶

Renegotiation of sessions is not supported, as it is not supported by TLS 1.3. If a future version of TLS supports renegotiation, this RFC should be updated to indicate whether there are any additional requirements related to its use.¶

### 3.2. TLS Cipher Suites, Extensions, and Protocol Invariants

Section 9 of [RFC8446] requires that, in the absence of application profiles, certain cipher suites, TLS extensions, and TLS protocol invariants be mandatory to implement. This document does not specify an application profile; hence, all the compliance requirements in [RFC8446] apply.¶

## 4. MIB Module Definitions

This SNMP-TLS-TM-MIB module imports items from RFCs 2578, 2579, and 2580 [STD58], as well as RFCs 3411 and 3413 [STD62]. It also references [RFC1123], [RFC5246], [RFC5280], [RFC5591], [RFC5890], [RFC5952], [RFC5953], [RFC6353], and RFC 2579 [STD58].¶

    <CODE BEGINS> file "SNMP-TLS-TM-MIB"

    SNMP-TLS-TM-MIB DEFINITIONS ::= BEGIN

    IMPORTS
        MODULE-IDENTITY, OBJECT-TYPE,
        OBJECT-IDENTITY, mib-2, snmpDomains,
        Counter32, Unsigned32, Gauge32, NOTIFICATION-TYPE
          FROM SNMPv2-SMI            -- RFC 2578 or any update thereof
        TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType,
        AutonomousType
          FROM SNMPv2-TC             -- RFC 2579 or any update thereof
        MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
          FROM SNMPv2-CONF           -- RFC 2580 or any update thereof
        SnmpAdminString
          FROM SNMP-FRAMEWORK-MIB    -- RFC 3411 or any update thereof
        snmpTargetParamsName, snmpTargetAddrName
          FROM SNMP-TARGET-MIB       -- RFC 3413 or any update thereof
        ;

    snmpTlstmMIB MODULE-IDENTITY
        LAST-UPDATED "202311080000Z"

        ORGANIZATION "Operations and Management Area Working Group
                      <mailto:opsawg@ietf.org>"
        CONTACT-INFO
                "Author: Kenneth Vaughn
                         <mailto:kvaughn@trevilon.com>"
        DESCRIPTION
           "This is the MIB module for the TLS Transport Model
            (TLSTM).

            Copyright (c) 2023 IETF Trust and the persons identified
            as authors of the code.  All rights reserved.

            Redistribution and use in source and binary forms,
            with or without modification, is permitted pursuant
            to, and subject to the license terms contained in,
            the Revised BSD License set forth in Section 4.c
            of the IETF Trust's Legal Provisions Relating to IETF
            Documents (https://trustee.ietf.org/license-info).

            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 (RFC 2119)
            (RFC 8174) when, and only when, they appear in all
            capitals, as shown here."

            REVISION    "202311080000Z"
            DESCRIPTION
               "This version of this MIB module is part of
                RFC 9456; see the RFC itself for full legal
                notices.  This version does the following:

                   1) Updates the definition of SnmpTLSFingerprint
                      to clarify the registry used for the one-octet
                      hash algorithm identifier.

                   2) Capitalizes key words in conformance with
                      BCP 14.

                   3) Replaces 'may not' with 'MUST NOT' to clarify
                      intent in several locations.

                   4) Replaces 'may not' with a clarification within
                      the definition of SnmpTLSAddress.

                   5) Applies cosmetic grammar improvements and
                      reformatting causing whitespace changes."

           REVISION     "201107190000Z"
           DESCRIPTION
              "This version of this MIB module is part of
               RFC 6353; see the RFC itself for full legal
               notices.  The only change was to introduce
               new wording to reflect required changes for
               Internationalized Domain Names for Applications
               (IDNA) addresses in the SnmpTLSAddress textual
               convention (TC)."

           REVISION     "201005070000Z"
           DESCRIPTION
              "This version of this MIB module is part of
               RFC 5953; see the RFC itself for full legal
               notices."
        ::= { mib-2 198 }

    -- ************************************************
    -- subtrees of the SNMP-TLS-TM-MIB
    -- ************************************************

    snmpTlstmNotifications OBJECT IDENTIFIER ::= { snmpTlstmMIB 0 }
    snmpTlstmIdentities    OBJECT IDENTIFIER ::= { snmpTlstmMIB 1 }
    snmpTlstmObjects       OBJECT IDENTIFIER ::= { snmpTlstmMIB 2 }
    snmpTlstmConformance   OBJECT IDENTIFIER ::= { snmpTlstmMIB 3 }
    snmpTlstmHashAlgorithms OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "A node used to register hashing algorithm identifiers
            recorded in the IANA 'SNMP-TLSTM HashAlgorithms' registry."
        ::= { snmpTlstmMIB 4 }

    -- ************************************************
    -- snmpTlstmObjects - Objects
    -- ************************************************

    snmpTLSTCPDomain OBJECT-IDENTITY
        STATUS      current
        DESCRIPTION
           "The OBJECT IDENTIFIER representing the TDomain for the
            SNMP over TLS via TCP transport domain.  The
            corresponding transport address is of type SnmpTLSAddress.

            The securityName prefix to be associated with the
            snmpTLSTCPDomain is 'tls'.  This prefix MAY be used by
            security models or other components to identify which secure
            transport infrastructure authenticated a securityName."
        REFERENCE
          "TDomain, as defined in RFC 2579: Textual Conventions
           for SMIv2"
        ::= { snmpDomains 8 }

    snmpDTLSUDPDomain OBJECT-IDENTITY
        STATUS      current
        DESCRIPTION
           "The OBJECT IDENTIFIER representing the TDomain for the
            SNMP over DTLS via UDP transport domain.  The
            corresponding transport address is of type SnmpTLSAddress.

            The securityName prefix to be associated with the
            snmpDTLSUDPDomain is 'dtls'.  This prefix MAY be used by
            security models or other components to identify which secure
            transport infrastructure authenticated a securityName."
        REFERENCE
          "TDomain, as defined in RFC 2579: Textual Conventions
           for SMIv2"
        ::= { snmpDomains 9 }

    SnmpTLSAddress ::= TEXTUAL-CONVENTION
        DISPLAY-HINT "1a"
        STATUS       current
        DESCRIPTION
           "Represents an IPv4 address, an IPv6 address, or an
            ASCII-encoded host name and port number.

            An IPv4 address MUST be in dotted decimal format followed
            by a colon ':' (ASCII character 0x3A) and a decimal
            port number in ASCII.

            An IPv6 address MUST be a colon-separated format (as
            described in RFC 5952), surrounded by square brackets
            ('[', ASCII character 0x5B, and ']', ASCII character
            0x5D), followed by a colon ':' (ASCII character 0x3A)
            and a decimal port number in ASCII.

            A host name MUST be in ASCII (as per RFC 1123);
            internationalized host names MUST be encoded as A-labels as
            specified in RFC 5890.  The host name is followed by a
            colon ':' (ASCII character 0x3A) and a decimal port
            number in ASCII.  The name SHOULD be fully qualified
            whenever possible.

            Values of this textual convention are not guaranteed to be
            directly usable as transport-layer addressing information,
            potentially requiring additional processing, such as
            run-time resolution.  As such, applications that write
            them MUST be prepared for handling errors if such values
            are not supported or cannot be resolved (if resolution
            occurs at the time of the management operation).

            The DESCRIPTION clause of TransportAddress objects that
            may have SnmpTLSAddress values MUST fully describe how
            (and when) such names are to be resolved to IP addresses
            and vice versa.

            This textual convention SHOULD NOT be used directly in
            object definitions, since it restricts addresses to a
            specific format.  However, if it is used, it MAY be used
            either on its own or in conjunction with
            TransportAddressType or TransportDomain as a pair.

            When this textual convention is used as a syntax of an
            index object, there may be issues with the limit of 128
            sub-identifiers specified in SMIv2 (STD 58).  It is
            RECOMMENDED that all MIB documents using this textual
            convention make explicit any limitations on index
            component lengths that management software MUST observe.
            This MAY be done by either 1) including SIZE constraints
            on the index components or 2) specifying applicable
            constraints in the conceptual row's DESCRIPTION clause or
            in the surrounding documentation."
        REFERENCE
          "RFC 1123: Requirements for Internet Hosts - Application and
                     Support
           RFC 5890: Internationalized Domain Names for Applications
                     (IDNA): Definitions and Document Framework
           RFC 5952: A Recommendation for IPv6 Address Text
                     Representation"
        SYNTAX       OCTET STRING (SIZE (1..255))

    SnmpTLSFingerprint ::= TEXTUAL-CONVENTION
        DISPLAY-HINT "1x:1x"
        STATUS       current
        DESCRIPTION
           "A fingerprint value that can be used to uniquely reference
            other data of potentially arbitrary length.

            An SnmpTLSFingerprint value is composed of a one-octet
            hashing algorithm identifier followed by the fingerprint
            value.  The one-octet identifier value encoded is taken
            from the IANA 'SNMP-TLSTM HashAlgorithms' registry.  The
            remaining octets of the SnmpTLSFingerprint value are
            filled using the results of the hashing algorithm.

            Historically, the one-octet hashing algorithm identifier
            was based on the IANA 'TLS HashAlgorithm' registry
            (RFC 5246); however, this registry is no longer in use for
            TLS 1.3 and above and is not expected to have any new
            registrations added to it.  To allow the fingerprint
            algorithm to support additional hashing algorithms that
            might be used by later versions of (D)TLS, the octet value
            encoded is now taken from the IANA
            'SNMP-TLSTM HashAlgorithms' registry.  The initial values
            within this registry are identical to the values in the
            'TLS HashAlgorithm' registry but can be extended to
            support new hashing algorithms as needed.

            This textual convention allows for a zero-length (blank)
            SnmpTLSFingerprint value for use in tables where the
            fingerprint value MAY be optional.  MIB definitions or
            implementations MAY refuse to accept a zero-length value
            as appropriate."
        REFERENCE
          "RFC 5246: The Transport Layer Security (TLS) Protocol
                     Version 1.2
           https://www.iana.org/assignments/smi-numbers/"
        SYNTAX OCTET STRING (SIZE (0..255))

    -- Identities for use in the snmpTlstmCertToTSNTable

    snmpTlstmCertToTSNMIdentities OBJECT IDENTIFIER ::=
                                  { snmpTlstmIdentities 1 }

    snmpTlstmCertSpecified OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Directly specifies the tmSecurityName to be used for this
            certificate.  The value of the tmSecurityName to use is
            specified in the 'snmpTlstmCertToTSNData' column.  The
            'snmpTlstmCertToTSNData' column MUST contain a
            non-zero-length SnmpAdminString-compliant value, or the
            mapping described in this row MUST be considered a
            failure."
        ::= { snmpTlstmCertToTSNMIdentities 1 }

    snmpTlstmCertSANRFC822Name OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Maps a subjectAltName's rfc822Name to a tmSecurityName.
            The local-part of the rfc822Name is passed unaltered, but
            the domain of the name MUST be passed in lowercase.
            This mapping results in a 1:1 correspondence between
            equivalent subjectAltName rfc822Name values and
            tmSecurityName values, except that the domain of the
            name MUST be passed in lowercase.

            Example rfc822Name field:  FooBar@Example.COM is mapped to
            tmSecurityName: FooBar@example.com."
        ::= { snmpTlstmCertToTSNMIdentities 2 }

    snmpTlstmCertSANDNSName OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Maps a subjectAltName's dNSName to a tmSecurityName after
            first converting it to all lowercase (RFC 5280 does not
            specify converting to lowercase, so this involves an extra
            step).  This mapping results in a 1:1 correspondence
            between subjectAltName dNSName values and the
            tmSecurityName values."
        REFERENCE
          "RFC 5280: Internet X.509 Public Key Infrastructure
                     Certificate and Certificate Revocation
                     List (CRL) Profile"
        ::= { snmpTlstmCertToTSNMIdentities 3 }

    snmpTlstmCertSANIpAddress OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Maps a subjectAltName's iPAddress to a tmSecurityName by
            transforming the binary-encoded address as follows:

               1) For IPv4, the value is converted into a
                  decimal-dotted quad address (e.g., '192.0.2.1').

               2) For IPv6 addresses, the value is converted into a
                  32-character all-lowercase hexadecimal string
                  without any colon separators.

            This mapping results in a 1:1 correspondence between
            subjectAltName iPAddress values and the tmSecurityName
            values.

            The resulting length of an encoded IPv6 address is the
            maximum length supported by the View-based Access Control
            Model (VACM).  Using an IPv6 address while the value of
            snmpTsmConfigurationUsePrefix is 'true' (see the
            SNMP-TSM-MIB, as defined in RFC 5591) will result in
            securityName lengths that exceed what the VACM can handle."
           REFERENCE
             "RFC 5591: Transport Security Model for the Simple Network
                        Management Protocol (SNMP)"
        ::= { snmpTlstmCertToTSNMIdentities 4 }

    snmpTlstmCertSANAny OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Maps any of the following fields using the corresponding
            mapping algorithms:

            |------------+----------------------------|
            | Type       | Algorithm                  |
            |------------+----------------------------|
            | rfc822Name | snmpTlstmCertSANRFC822Name |
            | dNSName    | snmpTlstmCertSANDNSName    |
            | iPAddress  | snmpTlstmCertSANIpAddress  |
            |------------+----------------------------|

            The first subjectAltName value contained in the certificate
            that matches any of the above types MUST be used when
            deriving the tmSecurityName.  The mapping algorithm
            specified in the 'Algorithm' column of the corresponding
            row MUST be used to derive the tmSecurityName.

            This mapping results in a 1:1 correspondence between
            subjectAltName values and tmSecurityName values.  The
            three sub-mapping algorithms produced by this combined
            algorithm cannot produce conflicting results between
            themselves."
        ::= { snmpTlstmCertToTSNMIdentities 5 }

    snmpTlstmCertCommonName OBJECT-IDENTITY
        STATUS        current
        DESCRIPTION
           "Maps a certificate's CommonName to a tmSecurityName after
            converting it to a UTF-8 encoding.  The usage of
            CommonNames is deprecated, and users are encouraged to use
            subjectAltName mapping methods instead.  This mapping
            results in a 1:1 correspondence between certificate
            CommonName values and tmSecurityName values."
        ::= { snmpTlstmCertToTSNMIdentities 6 }

    -- The snmpTlstmSession Group

    snmpTlstmSession         OBJECT IDENTIFIER ::= { snmpTlstmObjects 1 }

    snmpTlstmSessionOpens  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an openSession() request has been
            executed as a (D)TLS client, regardless of whether it
            succeeded or failed."
        ::= { snmpTlstmSession 1 }

    snmpTlstmSessionClientCloses  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times a closeSession() request has been
            executed as a (D)TLS client, regardless of whether it
            succeeded or failed."
        ::= { snmpTlstmSession 2 }

    snmpTlstmSessionOpenErrors  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an openSession() request failed to
            open a session as a (D)TLS client, for any reason."
        ::= { snmpTlstmSession 3 }

    snmpTlstmSessionAccepts  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times a (D)TLS server has accepted a new
            connection from a client and has received at least one
            SNMP message through it."
        ::= { snmpTlstmSession 4 }

    snmpTlstmSessionServerCloses  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times a closeSession() request has been
            executed as a (D)TLS server, regardless of whether it
            succeeded or failed."
        ::= { snmpTlstmSession 5 }

    snmpTlstmSessionNoSessions  OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an outgoing message was dropped
            because the session associated with the passed
            tmStateReference was no longer (or never) available."
        ::= { snmpTlstmSession 6 }

    snmpTlstmSessionInvalidClientCertificates OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an incoming session was not
            established on a (D)TLS server because the presented
            client certificate was invalid.  Reasons for invalidation
            include, but are not limited to, cryptographic validation
            failures or lack of a suitable mapping row in the
            snmpTlstmCertToTSNTable."
        ::= { snmpTlstmSession 7 }

    snmpTlstmSessionUnknownServerCertificate OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an outgoing session was not
            established on a (D)TLS client because the server
            certificate presented by an SNMP over (D)TLS server was
            invalid because no configured fingerprint or Certification
            Authority (CA) was acceptable to validate it.  This may
            result because there was no entry in the
            snmpTlstmAddrTable or because no path to a known CA could
            be found."
        ::= { snmpTlstmSession 8 }

    snmpTlstmSessionInvalidServerCertificates OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of times an outgoing session was not
            established on a (D)TLS client because the server
            certificate presented by an SNMP over (D)TLS server could
            not be validated even if the fingerprint or expected
            validation path was known.  That is, a cryptographic
            validation error occurred during certificate validation
            processing.

            Reasons for invalidation include, but are not limited to,
            cryptographic validation failures."
        ::= { snmpTlstmSession 9 }

    snmpTlstmSessionInvalidCaches OBJECT-TYPE
        SYNTAX       Counter32
        MAX-ACCESS   read-only
        STATUS       current
        DESCRIPTION
           "The number of outgoing messages dropped because the
            tmStateReference referred to an invalid cache."
        ::= { snmpTlstmSession 10 }

    -- Configuration Objects

    snmpTlstmConfig          OBJECT IDENTIFIER ::= { snmpTlstmObjects 2 }

    -- Certificate mapping

    snmpTlstmCertificateMapping OBJECT IDENTIFIER ::=
                                { snmpTlstmConfig 1 }

    snmpTlstmCertToTSNCount OBJECT-TYPE
        SYNTAX      Gauge32
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "A count of the number of entries in the
            snmpTlstmCertToTSNTable."
        ::= { snmpTlstmCertificateMapping 1 }

    snmpTlstmCertToTSNTableLastChanged OBJECT-TYPE
        SYNTAX      TimeStamp
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "The value of sysUpTime.0 when the snmpTlstmCertToTSNTable
            was last modified through any means, or 0 if it has not
            been modified since the command responder was started."
        ::= { snmpTlstmCertificateMapping 2 }

    snmpTlstmCertToTSNTable OBJECT-TYPE
        SYNTAX      SEQUENCE OF SnmpTlstmCertToTSNEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "This table is used by a (D)TLS server to map the (D)TLS
            client's presented X.509 certificate to a tmSecurityName.

            On an incoming (D)TLS/SNMP connection, the client's
            presented certificate either MUST be validated based on an
            established trust anchor or MUST directly match a
            fingerprint in this table.  This table does not provide
            any mechanisms for configuring the trust anchors; the
            transfer of any needed trusted certificates for path
            validation is expected to occur through an out-of-band
            transfer.

            Once the certificate has been found acceptable (either via
            path validation or by directly matching a fingerprint in
            this table), this table is consulted to determine the
            appropriate tmSecurityName to identify with the remote
            connection.  This is done by considering each active row
            from this table in prioritized order according to its
            snmpTlstmCertToTSNID value.  Each row's
            snmpTlstmCertToTSNFingerprint value determines whether the
            row is a match for the incoming connection:

               1) If the row's snmpTlstmCertToTSNFingerprint value
                  identifies the presented certificate, then consider
                  the row as a successful match.

               2) If the row's snmpTlstmCertToTSNFingerprint value
                  identifies a locally held copy of a trusted CA
                  certificate and that CA certificate was used to
                  validate the path to the presented certificate, then
                  consider the row as a successful match.

            Once a matching row has been found, the
            snmpTlstmCertToTSNMapType value can be used to determine
            how the tmSecurityName to associate with the session
            should be determined.  See the 'snmpTlstmCertToTSNMapType'
            column's DESCRIPTION clause for details on determining the
            tmSecurityName value.  If it is impossible to determine a
            tmSecurityName from the row's data combined with the data
            presented in the certificate, then additional rows MUST be
            searched to look for another potential match.  If a
            resulting tmSecurityName mapped from a given row is not
            compatible with the needed requirements of a
            tmSecurityName (e.g., the VACM imposes a 32-octet-maximum
            length and the certificate-derived securityName could be
            longer), then it MUST be considered an invalid match and
            additional rows MUST be searched to look for another
            potential match.

            If no matching and valid row can be found, the connection
            MUST be closed and SNMP messages MUST NOT be accepted over
            it.

            Missing values of snmpTlstmCertToTSNID are acceptable, and
            implementations SHOULD continue to the
            next-highest-numbered row.  It is RECOMMENDED that
            administrators skip index values to leave room for the
            insertion of future rows (for example, use values of 10
            and 20 when creating initial rows).

            Users are encouraged to make use of certificates with
            subjectAltName fields that can be used as tmSecurityNames.
            This allows all child certificates of a single root CA
            certificate to include a subjectAltName that maps directly
            to a tmSecurityName via a 1:1 transformation.  However,
            this table is flexible, to allow for situations where
            existing deployed certificate infrastructures do not provide
            adequate subjectAltName values for use as tmSecurityNames.
            Certificates MAY also be mapped to tmSecurityNames using
            the CommonName portion of the Subject field.  However, the
            usage of the CommonName field is deprecated, and thus this
            usage is NOT RECOMMENDED.  Direct mapping from each
            individual certificate fingerprint to a tmSecurityName is
            also possible but requires one entry in the table per
            tmSecurityName and requires more management operations to
            completely configure a device."
        ::= { snmpTlstmCertificateMapping 3 }

    snmpTlstmCertToTSNEntry OBJECT-TYPE
        SYNTAX      SnmpTlstmCertToTSNEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "A row in the snmpTlstmCertToTSNTable that specifies a
            mapping for an incoming (D)TLS certificate to a
            tmSecurityName to use for a connection."
        INDEX   { snmpTlstmCertToTSNID }
        ::= { snmpTlstmCertToTSNTable 1 }

    SnmpTlstmCertToTSNEntry ::= SEQUENCE {
        snmpTlstmCertToTSNID           Unsigned32,
        snmpTlstmCertToTSNFingerprint  SnmpTLSFingerprint,
        snmpTlstmCertToTSNMapType      AutonomousType,
        snmpTlstmCertToTSNData         OCTET STRING,
        snmpTlstmCertToTSNStorageType  StorageType,
        snmpTlstmCertToTSNRowStatus    RowStatus
    }

    snmpTlstmCertToTSNID OBJECT-TYPE
        SYNTAX      Unsigned32 (1..4294967295)
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "A unique, prioritized index for the given entry.  Lower
            numbers indicate a higher priority."
        ::= { snmpTlstmCertToTSNEntry 1 }

    snmpTlstmCertToTSNFingerprint OBJECT-TYPE
        SYNTAX      SnmpTLSFingerprint (SIZE (1..255))
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "A cryptographic hash of an X.509 certificate.  The results
            of a successful matching fingerprint to either the trusted
            CA in the certificate validation path or the certificate
            itself is dictated by the 'snmpTlstmCertToTSNMapType'
            column."
        ::= { snmpTlstmCertToTSNEntry 2 }

    snmpTlstmCertToTSNMapType OBJECT-TYPE
        SYNTAX      AutonomousType
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "Specifies the mapping type for deriving a tmSecurityName
            from a certificate.  Details for mapping of a particular
            type SHALL be specified in the DESCRIPTION clause of the
            OBJECT-IDENTITY that describes the mapping.  If a mapping
            succeeds, it will return a tmSecurityName for use by the
            TLSTM and processing will stop.

            If the resulting mapped value is not compatible with the
            needed requirements of a tmSecurityName (e.g., the VACM
            imposes a 32-octet-maximum length and the
            certificate-derived securityName could be longer), then
            future rows MUST be searched for additional
            snmpTlstmCertToTSNFingerprint matches to look for a
            mapping that succeeds.

            Suitable values for assigning to this object that are
            defined within the SNMP-TLS-TM-MIB can be found in the
            snmpTlstmCertToTSNMIdentities portion of the MIB tree."
        DEFVAL { snmpTlstmCertSpecified }
        ::= { snmpTlstmCertToTSNEntry 3 }

    snmpTlstmCertToTSNData OBJECT-TYPE
        SYNTAX      OCTET STRING (SIZE (0..1024))
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "Auxiliary data used as optional configuration information
            for a given mapping specified by the
            'snmpTlstmCertToTSNMapType' column.  Only some mapping
            systems will make use of this column.  The value in this
            column MUST be ignored for any mapping type that does not
            require that data be present in this column."
        DEFVAL { "" }
        ::= { snmpTlstmCertToTSNEntry 4 }

    snmpTlstmCertToTSNStorageType OBJECT-TYPE
        SYNTAX       StorageType
        MAX-ACCESS   read-create
        STATUS       current
        DESCRIPTION
           "The storage type for this conceptual row.  Conceptual rows
            having the value 'permanent' need not allow write-access
            to any columnar objects in the row."
        DEFVAL      { nonVolatile }
        ::= { snmpTlstmCertToTSNEntry 5 }

    snmpTlstmCertToTSNRowStatus OBJECT-TYPE
        SYNTAX      RowStatus
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "The status of this conceptual row.  This object MAY be
            used to create or remove rows from this table.

            To create a row in this table, an administrator MUST set
            this object to either createAndGo(4) or createAndWait(5).

            Until instances of all corresponding columns are
            appropriately configured, the value of the corresponding
            instance of the 'snmpTlstmParamsRowStatus' column is
            notReady(3).

            In particular, a newly created row cannot be made active
            until the corresponding 'snmpTlstmCertToTSNFingerprint',
            'snmpTlstmCertToTSNMapType', and 'snmpTlstmCertToTSNData'
            columns have been set.

            The following objects MUST NOT be modified while the
            value of this object is active(1):

               - snmpTlstmCertToTSNFingerprint
               - snmpTlstmCertToTSNMapType
               - snmpTlstmCertToTSNData

            An attempt to set these objects while the value of
            snmpTlstmParamsRowStatus is active(1) will result in
            an inconsistentValue error."
        ::= { snmpTlstmCertToTSNEntry 6 }

    -- Maps tmSecurityNames to certificates for use by the
    -- SNMP-TARGET-MIB

    snmpTlstmParamsCount OBJECT-TYPE
        SYNTAX      Gauge32
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "A count of the number of entries in the
            snmpTlstmParamsTable."
        ::= { snmpTlstmCertificateMapping 4 }

    snmpTlstmParamsTableLastChanged OBJECT-TYPE
        SYNTAX      TimeStamp
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "The value of sysUpTime.0 when the snmpTlstmParamsTable
            was last modified through any means, or 0 if it has not
            been modified since the command responder was started."
        ::= { snmpTlstmCertificateMapping 5 }

    snmpTlstmParamsTable OBJECT-TYPE
        SYNTAX      SEQUENCE OF SnmpTlstmParamsEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "This table is used by a (D)TLS client when a (D)TLS
            connection is being set up using an entry in the
            SNMP-TARGET-MIB.  It extends the SNMP-TARGET-MIB's
            snmpTargetParamsTable with a fingerprint of a certificate
            to use when establishing such a (D)TLS connection."
        ::= { snmpTlstmCertificateMapping 6 }

    snmpTlstmParamsEntry OBJECT-TYPE
        SYNTAX      SnmpTlstmParamsEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "A conceptual row containing a fingerprint hash of a
            locally held certificate for a given
            snmpTargetParamsEntry.  The values in this row SHOULD be
            ignored if the connection that needs to be established, as
            indicated by the SNMP-TARGET-MIB infrastructure, is not a
            certificate-based and (D)TLS-based connection.  The
            connection SHOULD NOT be established if the certificate
            fingerprint stored in this entry does not point to a valid
            locally held certificate or if it points to an unusable
            certificate (such as might happen when the certificate's
            expiration date has been reached)."
        INDEX    { IMPLIED snmpTargetParamsName }
        ::= { snmpTlstmParamsTable 1 }

    SnmpTlstmParamsEntry ::= SEQUENCE {
        snmpTlstmParamsClientFingerprint SnmpTLSFingerprint,
        snmpTlstmParamsStorageType       StorageType,
        snmpTlstmParamsRowStatus         RowStatus
    }

    snmpTlstmParamsClientFingerprint OBJECT-TYPE
        SYNTAX      SnmpTLSFingerprint
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "This object stores the hash of the public portion of a
            locally held X.509 certificate.  The X.509 certificate,
            its public key, and the corresponding private key will be
            used when initiating a (D)TLS connection as a (D)TLS
            client."
        ::= { snmpTlstmParamsEntry 1 }

    snmpTlstmParamsStorageType OBJECT-TYPE
        SYNTAX       StorageType
        MAX-ACCESS   read-create
        STATUS       current
        DESCRIPTION
           "The storage type for this conceptual row.  Conceptual rows
            having the value 'permanent' need not allow write-access
            to any columnar objects in the row."
        DEFVAL      { nonVolatile }
        ::= { snmpTlstmParamsEntry 2 }

    snmpTlstmParamsRowStatus OBJECT-TYPE
        SYNTAX      RowStatus
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "The status of this conceptual row.  This object MAY be
            used to create or remove rows from this table.

            To create a row in this table, an administrator MUST set
            this object to either createAndGo(4) or createAndWait(5).

            Until instances of all corresponding columns are
            appropriately configured, the value of the corresponding
            instance of the 'snmpTlstmParamsRowStatus' column is
            notReady(3).

            In particular, a newly created row cannot be made active
            until the corresponding 'snmpTlstmParamsClientFingerprint'
            column has been set.

            The snmpTlstmParamsClientFingerprint object MUST NOT be
            modified while the value of this object is active(1).

            An attempt to set these objects while the value of
            snmpTlstmParamsRowStatus is active(1) will result in
            an inconsistentValue error."
        ::= { snmpTlstmParamsEntry 3 }

    snmpTlstmAddrCount OBJECT-TYPE
        SYNTAX      Gauge32
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "A count of the number of entries in the
            snmpTlstmAddrTable."
        ::= { snmpTlstmCertificateMapping 7 }

    snmpTlstmAddrTableLastChanged OBJECT-TYPE
        SYNTAX      TimeStamp
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
           "The value of sysUpTime.0 when the snmpTlstmAddrTable
            was last modified through any means, or 0 if it has not
            been modified since the command responder was started."
        ::= { snmpTlstmCertificateMapping 8 }

    snmpTlstmAddrTable OBJECT-TYPE
        SYNTAX      SEQUENCE OF SnmpTlstmAddrEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "This table is used by a (D)TLS client when a (D)TLS
            connection is being set up using an entry in the
            SNMP-TARGET-MIB.  It extends the SNMP-TARGET-MIB's
            snmpTargetAddrTable so that the client can verify that the
            correct server has been reached.  This verification can
            use either 1) a certificate fingerprint or 2) an
            identity authenticated via certification path validation.

            If there is an active row in this table corresponding to
            the entry in the SNMP-TARGET-MIB that was used to
            establish the connection and the row's
            'snmpTlstmAddrServerFingerprint' column has a non-empty
            value, then the server's presented certificate is compared
            with the snmpTlstmAddrServerFingerprint value (and the
            'snmpTlstmAddrServerIdentity' column is ignored).  If the
            fingerprint matches, the verification has succeeded.  If
            the fingerprint does not match, then the connection MUST
            be closed.

            If the server's presented certificate has passed
            certification path validation (RFC 5280) to a configured
            trust anchor and an active row exists with a zero-length
            snmpTlstmAddrServerFingerprint value, then the
            'snmpTlstmAddrServerIdentity' column contains the expected
            host name.  This expected host name is then compared
            against the server's certificate as follows:

               - Implementations MUST support matching the expected
                 host name against a dNSName in the subjectAltName
                 extension field and MAY support checking the name
                 against the CommonName portion of the subject
                 distinguished name.

               - The '*' (ASCII 0x2A) wildcard character is allowed in
                 the dNSName of the subjectAltName extension (and in
                 CommonName, if used to store the host name), but
                 only as the leftmost (least significant) DNS label
                 in that value.  This wildcard matches any leftmost
                 DNS label in the server name.  That is, the subject
                 *.example.com matches the server names a.example.com
                 and b.example.com but does not match example.com or
                 a.b.example.com.  Implementations MUST support
                 wildcards in certificates as specified above but MAY
                 provide a configuration option to disable them.

               - If the locally configured name is an
                 internationalized domain name, conforming
                 implementations MUST convert it to the ASCII
                 Compatible Encoding (ACE) format for performing
                 comparisons, as specified in Section 7 of RFC 5280.

            If the expected host name fails these conditions, then the
            connection MUST be closed.

            If there is no row in this table corresponding to the
            entry in the SNMP-TARGET-MIB and the server can be
            authorized by another, implementation-dependent means,
            then the connection MAY still proceed."
        ::= { snmpTlstmCertificateMapping 9 }

    snmpTlstmAddrEntry OBJECT-TYPE
        SYNTAX      SnmpTlstmAddrEntry
        MAX-ACCESS  not-accessible
        STATUS      current
        DESCRIPTION
           "A conceptual row containing a copy of a certificate's
            fingerprint for a given snmpTargetAddrEntry.  The values
            in this row SHOULD be ignored if the connection that needs
            to be established, as indicated by the SNMP-TARGET-MIB
            infrastructure, is not a (D)TLS-based connection.  If an
            snmpTlstmAddrEntry exists for a given snmpTargetAddrEntry,
            then the presented server certificate MUST match or the
            connection MUST NOT be established.  If a row in this
            table does not exist to match an snmpTargetAddrEntry row,
            then the connection SHOULD still proceed if some other
            certification path validation algorithm (e.g., RFC 5280)
            can be used."
        INDEX    { IMPLIED snmpTargetAddrName }
        ::= { snmpTlstmAddrTable 1 }

    SnmpTlstmAddrEntry ::= SEQUENCE {
        snmpTlstmAddrServerFingerprint    SnmpTLSFingerprint,
        snmpTlstmAddrServerIdentity       SnmpAdminString,
        snmpTlstmAddrStorageType          StorageType,
        snmpTlstmAddrRowStatus            RowStatus
    }

    snmpTlstmAddrServerFingerprint OBJECT-TYPE
        SYNTAX      SnmpTLSFingerprint
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "A cryptographic hash of a public X.509 certificate.  This
            object should store the hash of the public X.509
            certificate that the remote server should present during
            the (D)TLS connection setup.  The fingerprint of the
            presented certificate and this hash value MUST match
            exactly, or the connection MUST NOT be established."
        DEFVAL { "" }
        ::= { snmpTlstmAddrEntry 1 }

    snmpTlstmAddrServerIdentity OBJECT-TYPE
        SYNTAX      SnmpAdminString
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "The reference identity to check against the identity
            presented by the remote system."
        DEFVAL { "" }
        ::= { snmpTlstmAddrEntry 2 }

    snmpTlstmAddrStorageType OBJECT-TYPE
        SYNTAX       StorageType
        MAX-ACCESS   read-create
        STATUS       current
        DESCRIPTION
           "The storage type for this conceptual row.  Conceptual rows
            having the value 'permanent' need not allow write-access
            to any columnar objects in the row."
        DEFVAL      { nonVolatile }
        ::= { snmpTlstmAddrEntry 3 }

    snmpTlstmAddrRowStatus OBJECT-TYPE
        SYNTAX      RowStatus
        MAX-ACCESS  read-create
        STATUS      current
        DESCRIPTION
           "The status of this conceptual row.  This object may be
            used to create or remove rows from this table.

            To create a row in this table, an administrator MUST set
            this object to either createAndGo(4) or createAndWait(5).

            Until instances of all corresponding columns are
            appropriately configured, the value of the corresponding
            instance of the 'snmpTlstmAddrRowStatus' column is
            notReady(3).

            In particular, a newly created row cannot be made active
            until the corresponding 'snmpTlstmAddrServerFingerprint'
            column has been set.

            Rows MUST NOT be active if the
            'snmpTlstmAddrServerFingerprint' column is blank and the
            snmpTlstmAddrServerIdentity is set to '*', since this
            would insecurely accept any presented certificate.

            The snmpTlstmAddrServerFingerprint object MUST NOT be
            modified while the value of this object is active(1).

            An attempt to set these objects while the value of
            snmpTlstmAddrRowStatus is active(1) will result in
            an inconsistentValue error."
        ::= { snmpTlstmAddrEntry 4 }

    -- ************************************************
    --  snmpTlstmNotifications - Notifications Information
    -- ************************************************

    snmpTlstmServerCertificateUnknown NOTIFICATION-TYPE
        OBJECTS { snmpTlstmSessionUnknownServerCertificate }
        STATUS  current
        DESCRIPTION
           "Notification that the server certificate presented by an
            SNMP over (D)TLS server was invalid because no configured
            fingerprint or CA was acceptable to validate it.  This may
            be because there was no entry in the snmpTlstmAddrTable or
            because no path to a known CA could be found.

            To avoid notification loops, this notification MUST NOT be
            sent to servers that themselves have triggered the
            notification."
        ::= { snmpTlstmNotifications 1 }

    snmpTlstmServerInvalidCertificate NOTIFICATION-TYPE
        OBJECTS {
            snmpTlstmAddrServerFingerprint,
            snmpTlstmSessionInvalidServerCertificates
        }
        STATUS  current
        DESCRIPTION
           "Notification that the server certificate presented by an
            SNMP over (D)TLS server could not be validated even if the
            fingerprint or expected validation path was known.
            That is, a cryptographic validation error occurred during
            certificate validation processing.

            To avoid notification loops, this notification MUST NOT be
            sent to servers that themselves have triggered the
            notification."
        ::= { snmpTlstmNotifications 2 }

    -- ************************************************
    -- snmpTlstmCompliances - Conformance Information
    -- ************************************************

    snmpTlstmCompliances OBJECT IDENTIFIER ::= { snmpTlstmConformance 1 }

    snmpTlstmGroups OBJECT IDENTIFIER ::= { snmpTlstmConformance 2 }

    -- ************************************************
    -- Compliance statements
    -- ************************************************

    snmpTlstmCompliance MODULE-COMPLIANCE
        STATUS      current
        DESCRIPTION
           "The compliance statement for SNMP engines that support the
            SNMP-TLS-TM-MIB."
        MODULE
            MANDATORY-GROUPS { snmpTlstmStatsGroup,
                               snmpTlstmIncomingGroup,
                               snmpTlstmOutgoingGroup,
                               snmpTlstmNotificationGroup }
        ::= { snmpTlstmCompliances 1 }

    -- ************************************************
    -- Units of conformance
    -- ************************************************

    snmpTlstmStatsGroup OBJECT-GROUP
        OBJECTS {
            snmpTlstmSessionOpens,
            snmpTlstmSessionClientCloses,
            snmpTlstmSessionOpenErrors,
            snmpTlstmSessionAccepts,
            snmpTlstmSessionServerCloses,
            snmpTlstmSessionNoSessions,
            snmpTlstmSessionInvalidClientCertificates,
            snmpTlstmSessionUnknownServerCertificate,
            snmpTlstmSessionInvalidServerCertificates,
            snmpTlstmSessionInvalidCaches
        }
        STATUS      current
        DESCRIPTION
           "A collection of objects for maintaining statistical
            information of an SNMP engine that implements the SNMP
            TLSTM."
        ::= { snmpTlstmGroups 1 }

    snmpTlstmIncomingGroup OBJECT-GROUP
        OBJECTS {
            snmpTlstmCertToTSNCount,
            snmpTlstmCertToTSNTableLastChanged,
            snmpTlstmCertToTSNFingerprint,
            snmpTlstmCertToTSNMapType,
            snmpTlstmCertToTSNData,
            snmpTlstmCertToTSNStorageType,
            snmpTlstmCertToTSNRowStatus
        }
        STATUS      current
        DESCRIPTION
           "A collection of objects for maintaining incoming
            connection certificate mappings to tmSecurityNames of an
            SNMP engine that implements the SNMP TLSTM."
        ::= { snmpTlstmGroups 2 }

    snmpTlstmOutgoingGroup OBJECT-GROUP
        OBJECTS {
            snmpTlstmParamsCount,
            snmpTlstmParamsTableLastChanged,
            snmpTlstmParamsClientFingerprint,
            snmpTlstmParamsStorageType,
            snmpTlstmParamsRowStatus,
            snmpTlstmAddrCount,
            snmpTlstmAddrTableLastChanged,
            snmpTlstmAddrServerFingerprint,
            snmpTlstmAddrServerIdentity,
            snmpTlstmAddrStorageType,
            snmpTlstmAddrRowStatus
        }
        STATUS      current
        DESCRIPTION
           "A collection of objects for maintaining outgoing
            connection certificates to use when opening connections as
            a result of SNMP-TARGET-MIB settings."
        ::= { snmpTlstmGroups 3 }

    snmpTlstmNotificationGroup NOTIFICATION-GROUP
        NOTIFICATIONS {
            snmpTlstmServerCertificateUnknown,
            snmpTlstmServerInvalidCertificate
        }
        STATUS current
        DESCRIPTION
           "Notifications."
        ::= { snmpTlstmGroups 4 }

    END

    <CODE ENDS>

¶

## 5. Security Considerations

This document updates a transport model that permits SNMP to utilize (D)TLS security services. The security threats and how the TLSTM mitigates these threats are covered throughout this document and in [RFC6353]. Security considerations for TLS are described in Section 10 and Appendix E of TLS 1.3 [RFC8446]. Security considerations for DTLS are described in Section 11 of DTLS 1.3 [RFC9147].¶

Implementations should consider the latest recommendations on the use of (DTLS), such as those documented in [RFC9325].¶

SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example, by using IPsec), there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB module.¶

It is RECOMMENDED that only SNMPv3 messages using the Transport Security Model (TSM) or another secure-transport-aware security model be sent over the TLSTM transport.¶

## 6. IANA Considerations

IANA has created a new registry called "SNMP-TLSTM HashAlgorithms" within the "Structure of Management Information (SMI) Numbers (MIB Module Registrations)" group. The description of this registry is "iso.org.dod.internet.mgmt.mib-2.snmpTlstmMIB.snmpTlstmHashAlgorithms (1.3.6.1.2.1.198.4)".¶

The registry has the following fields: Value, Description, Recommended, and References. The range of values is zero to 255, with initial assignments shown in Section 2.1. The "Recommended" column indicates "Y" for hashing algorithms that are Standards Track and are deemed to be acceptable for widely applicable current use and "N" for hashing algorithms that reflect meanings that are not recommended (e.g., they do not provide sufficient security for modern systems, they are not Standards Track, and they have limited applicability). A blank field indicates that no recommendation is made (e.g., because the value is unassigned or left for private use).¶

This registry is expected to be updated infrequently; as such, its values are limited to one octet.¶

The policy for updates to the "SNMP-TLSTM HashAlgorithms" registry is Expert Review [RFC8126]. Registry requests should be sent to the <mailto:snmp-tlstm-reg-review@ietf.org> mailing list. Registration requests sent to the mailing list for review SHOULD use an appropriate subject (e.g., 'Request to register value in "SNMP-TLSTM HashAlgorithms" registry'). In addition, designated experts should consult with the <mailto:tls-reg-review@ietf.org> mailing list to make sure that any new hash algorithms are considered for inclusion in this registry.¶

Designated experts SHOULD ascertain the existence of suitable documentation that defines a hash algorithm and SHOULD also verify that the request does not conflict with or duplicate other entries in the registry. The experts should also provide a recommendation as to how the "Recommended" column of the registry should be updated. Only publicly available specifications that represent current industry- accepted practices should receive an assignment of "Y" in the "Recommended" column; all other specific assignments in the registry should receive an assignment of "N". Assignments that are nonspecific (e.g., reserved values) SHOULD NOT receive an assigned value for the "Recommended" column.¶

Within the three-week review period, the designated experts will either approve or deny the registration request, communicating this decision to the review list and IANA. Denials SHOULD 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 three weeks can be brought to the IESG's attention (using the <mailto:iesg@ietf.org> mailing list) for resolution.¶

IANA MUST only accept registry updates from the designated experts and SHOULD direct all requests for registration to the review mailing list. While future additions to the "TLS HashAlgorithm" registry (i.e., the registry from which the "SNMP-TLSTM HashAlgorithms" registry was spawned) are not expected, any future additions to the "TLS HashAlgorithm" registry MUST be consistent with the values assigned in the "SNMP-TLSTM HashAlgorithms" registry.¶

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 reviews 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.¶

## 7. References

### 7.1. Normative References

[RFC1123]
  Braden, R., Ed., "Requirements for Internet Hosts - Application and Support", STD 3, RFC 1123, DOI 10.17487/RFC1123, October 1989, <https://www.rfc-editor.org/info/rfc1123>.
[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>.
[RFC3410]
  Case, J., Mundy, R., Partain, D., and B. Stewart, "Introduction and Applicability Statements for Internet-Standard Management Framework", RFC 3410, DOI 10.17487/RFC3410, December 2002, <https://www.rfc-editor.org/info/rfc3410>.
[RFC5280]
  Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, <https://www.rfc-editor.org/info/rfc5280>.
[RFC5890]
  Klensin, J., "Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework", RFC 5890, DOI 10.17487/RFC5890, August 2010, <https://www.rfc-editor.org/info/rfc5890>.
[RFC5952]
  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 Address Text Representation", RFC 5952, DOI 10.17487/RFC5952, August 2010, <https://www.rfc-editor.org/info/rfc5952>.
[RFC6353]
  Hardaker, W., "Transport Layer Security (TLS) Transport Model for the Simple Network Management Protocol (SNMP)", STD 78, RFC 6353, DOI 10.17487/RFC6353, July 2011, <https://www.rfc-editor.org/info/rfc6353>.
[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>.
[RFC8446]
  Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, <https://www.rfc-editor.org/info/rfc8446>.
[STD58]
  McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
  McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.
  McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999.
  <https://www.rfc-editor.org/info/std58>
[STD62]
  Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, December 2002.
  Case, J., Harrington, D., Presuhn, R., and B. Wijnen, "Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3412, December 2002.
  Levi, D., Meyer, P., and B. Stewart, "Simple Network Management Protocol (SNMP) Applications", STD 62, RFC 3413, December 2002.
  Blumenthal, U. and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", STD 62, RFC 3414, December 2002.
  Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3415, December 2002.
  Presuhn, R., Ed., "Version 2 of the Protocol Operations for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3416, December 2002.
  Presuhn, R., Ed., "Transport Mappings for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3417, December 2002.
  Presuhn, R., Ed., "Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3418, December 2002.
  <https://www.rfc-editor.org/info/std62>

### 7.2. Informative References

[RFC5246]
  Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008, <https://www.rfc-editor.org/info/rfc5246>.
[RFC5591]
  Harrington, D. and W. Hardaker, "Transport Security Model for the Simple Network Management Protocol (SNMP)", STD 78, RFC 5591, DOI 10.17487/RFC5591, June 2009, <https://www.rfc-editor.org/info/rfc5591>.
[RFC5953]
  Hardaker, W., "Transport Layer Security (TLS) Transport Model for the Simple Network Management Protocol (SNMP)", RFC 5953, DOI 10.17487/RFC5953, August 2010, <https://www.rfc-editor.org/info/rfc5953>.
[RFC8126]
  Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, <https://www.rfc-editor.org/info/rfc8126>.
[RFC8422]
  Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier", RFC 8422, DOI 10.17487/RFC8422, August 2018, <https://www.rfc-editor.org/info/rfc8422>.
[RFC8447]
  Salowey, J. and S. Turner, "IANA Registry Updates for TLS and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018, <https://www.rfc-editor.org/info/rfc8447>.
[RFC8996]
  Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS 1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021, <https://www.rfc-editor.org/info/rfc8996>.
[RFC9147]
  Rescorla, E., Tschofenig, H., and N. Modadugu, "The Datagram Transport Layer Security (DTLS) Protocol Version 1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022, <https://www.rfc-editor.org/info/rfc9147>.
[RFC9150]
  Cam-Winget, N. and J. Visoky, "TLS 1.3 Authentication and Integrity-Only Cipher Suites", RFC 9150, DOI 10.17487/RFC9150, April 2022, <https://www.rfc-editor.org/info/rfc9150>.
[RFC9325]
  Sheffer, Y., Saint-Andre, P., and T. Fossati, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November 2022, <https://www.rfc-editor.org/info/rfc9325>.

## Acknowledgements

This document is based on [RFC6353]. This document was reviewed by the following people, who helped provide useful comments: Michaela Vanderveen, Joe Clarke, Jürgen Schönwälder, and Tom Petch.¶

## Author's Address