Transport Layer Security (TLS) Transport Model for the Simple Network Management Protocol (SNMP)

This document describes a Transport Model for the Simple Network Management Protocol (SNMP), that uses either the Transport Layer Security protocol or the Datagram Transport Layer Security (DTLS) protocol. The TLS and DTLS protocols provide authentication and privacy services for SNMP applications. This document describes how the TLS Transport Model (TLSTM) implements the needed features of a SNMP Transport Subsystem to make this protection possible in an interoperable way.

This transport model is designed to meet the security and operational needs of network administrators. It supports sending of SNMP messages over TLS/TCP and DTLS/UDP. The TLS mode can make use of TCP's improved support for larger packet sizes and the DTLS mode provides potentially superior operation in environments where a connectionless (e.g. UDP) transport is preferred. Both TLS and DTLS integrate well into existing public keying infrastructures.

This document also defines a portion of the Management Information Base (MIB) for use with network management protocols. In particular it defines objects for managing the TLS Transport Model for SNMP.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work in progress.”

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This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.

1. Introduction
    1.1. Conventions
2. The Transport Layer Security Protocol
3. How the TLSTM fits into the Transport Subsystem
    3.1. Security Capabilities of this Model
        3.1.1. Threats
        3.1.2. Message Protection
        3.1.3. (D)TLS Connections
    3.2. Security Parameter Passing
    3.3. Notifications and Proxy
4. Elements of the Model
    4.1. X.509 Certificates
        4.1.1. Provisioning for the Certificate
    4.2. (D)TLS Usage
    4.3. SNMP Services
        4.3.1. SNMP Services for an Outgoing Message
        4.3.2. SNMP Services for an Incoming Message
    4.4. Cached Information and References
        4.4.1. TLS Transport Model Cached Information
            4.4.1.1. tmSecurityName
            4.4.1.2. tmSessionID
            4.4.1.3. Session State
5. Elements of Procedure
    5.1. Procedures for an Incoming Message
        5.1.1. DTLS over UDP Processing for Incoming Messages
        5.1.2. Transport Processing for Incoming SNMP Messages
    5.2. Procedures for an Outgoing SNMP Message
    5.3. Establishing or Accepting a Session
        5.3.1. Establishing a Session as a Client
        5.3.2. Accepting a Session as a Server
    5.4. Closing a Session
6. MIB Module Overview
    6.1. Structure of the MIB Module
    6.2. Textual Conventions
    6.3. Statistical Counters
    6.4. Configuration Tables
        6.4.1. Notifications
    6.5. Relationship to Other MIB Modules
        6.5.1. MIB Modules Required for IMPORTS
7. MIB Module Definition
8. Operational Considerations
    8.1. Sessions
    8.2. Notification Receiver Credential Selection
    8.3. contextEngineID Discovery
    8.4. Transport Considerations
9. Security Considerations
    9.1. Certificates, Authentication, and Authorization
    9.2. (D)TLS Security Considerations
        9.2.1. TLS Version Requirements
        9.2.2. Perfect Forward Secrecy
    9.3. Use with SNMPv1/SNMPv2c Messages
    9.4. MIB Module Security
10. IANA Considerations
11. Acknowledgements
12. References
    12.1. Normative References
    12.2. Informative References
Appendix A. Target and Notification Configuration Example
    A.1. Configuring a Notification Originator
    A.2. Configuring TLSTM to Utilize a Simple Derivation of tmSecurityName
    A.3. Configuring TLSTM to Utilize Table-Driven Certificate Mapping
§ Author's Address

1. Introduction

The diagram shown below gives a conceptual overview of two SNMP entities communicating using the TLS Transport Model (shown as "TLS TM"). One entity contains a command responder and notification originator application, and the other a command generator and notification receiver application. It should be understood that this particular mix of application types is an example only and other combinations are equally valid. Note: this diagram shows the Transport Security Model (TSM) being used as the security model which is defined in [RFC5591] (Harrington, D. and W. Hardaker, “Transport Security Model for the Simple Network Management Protocol (SNMP),” June 2009.).

1.1. Conventions

For consistency with SNMP-related specifications, this document favors terminology as defined in STD 62, rather than favoring terminology that is consistent with non-SNMP specifications. This is consistent with the IESG decision to not require the SNMPv3 terminology be modified to match the usage of other non-SNMP specifications when SNMPv3 was advanced to Full 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.

Large portions of this document simultaneously refer to both TLS and DTLS when discussing TLSTM components that function equally with either protocol. "(D)TLS" is used in these places to indicate that the statement applies to either or both protocols as appropriate. When a distinction between the protocols is needed they are referred to independently through the use of "TLS" or "DTLS". The Transport Model, however, is named "TLS Transport Model" and refers not to the TLS or DTLS protocol but to the specification in this document, which includes support for both TLS and DTLS.

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

The User-Based Security Model (USM) [RFC3414] (Blumenthal, U. and B. Wijnen, “User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3),” December 2002.) is a mandatory-to-implement Security Model in STD 62. While (D)TLS and USM frequently refer to a user, the terminology preferred in RFC3411 and in this memo is "principal". A principal is the "who" on whose behalf services are provided or processing takes place. A principal can be, among other things, an individual acting in a particular role; a set of individuals, with each acting in a particular role; an application or a set of applications, or a combination of these within an administrative domain.

Throughout this document, the term "session" is used to refer to a secure association between two TLS Transport Models that permits the transmission of one or more SNMP messages within the lifetime of the session. The (D)TLS protocols also have 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 (D)TLS protocol's session.

2. The Transport Layer Security Protocol

3. How the TLSTM fits into the Transport Subsystem

The TLS Transport Model will establish a session between itself and the TLS Transport Model of another SNMP engine. The sending transport model passes unencrypted and unauthenticated messages from the Dispatcher to (D)TLS to be encrypted and authenticated, and the receiving transport model accepts decrypted and authenticated/integrity-checked incoming messages from (D)TLS and passes them to the Dispatcher.

After a TLS Transport Model session is established, SNMP messages can conceptually be sent through the session from one SNMP message Dispatcher to another SNMP Message Dispatcher. If multiple SNMP messages are needed to be passed between two SNMP applications they MAY be passed through the same session. A TLSTM implementation engine MAY choose to close the session to conserve resources.

The TLS Transport Model of an SNMP engine will perform the translation between (D)TLS-specific security parameters and SNMP- specific, model-independent parameters.

The diagram below depicts where the TLS Transport Model (shown as "(D)TLS TM") fits into the architecture described in RFC3411 and the Transport Subsystem:

3.1. Security Capabilities of this Model

3.1.1. Threats

3.1.2. Message Protection

The TLS Transport Model determines from (D)TLS the identity of the authenticated principal, the transport type and the transport address associated with an incoming message. The TLS Transport Model provides the identity and destination type and address to (D)TLS for outgoing messages.

When an application requests a session for a message it also requests a security level for that session. The TLS Transport Model MUST ensure that the (D)TLS connection provides security at least as high as the requested level of security. How the security level is translated into the algorithms used to provide data integrity and privacy is implementation-dependent. However, the NULL integrity and encryption algorithms MUST NOT be used to fulfill security level requests for authentication or privacy. Implementations MAY choose to force (D)TLS to only allow cipher_suites that provide both authentication and privacy to guarantee this assertion.

If a suitable interface between the TLS Transport Model and the (D)TLS Handshake Protocol is implemented to allow the selection of security level dependent algorithms (for example a security level to cipher_suites mapping table) then different security levels may be utilized by the application.

The authentication, integrity and privacy algorithms used by the (D)TLS Protocols may vary over time as the science of cryptography continues to evolve and the development of (D)TLS continues over time. Implementers are encouraged to plan for changes in operator trust of particular algorithms. Implementations SHOULD offer configuration settings for mapping algorithms to SNMPv3 security levels.

3.1.3. (D)TLS Connections

(D)TLS connections are opened by the TLS Transport Model during the elements of procedure for an outgoing SNMP message. Since the sender of a message initiates the creation of a (D)TLS connection if needed, the (D)TLS connection will already exist for an incoming message.

Implementations MAY choose to instantiate (D)TLS connections in anticipation of outgoing messages. This approach might be useful to ensure that a (D)TLS connection to a given target can be established before it becomes important to send a message over the (D)TLS connection. Of course, there is no guarantee that a pre-established session will still be valid when needed.

DTLS connections, when used over UDP, are uniquely identified within the TLS Transport Model by the combination of transportDomain, transportAddress, tmSecurityName, and requestedSecurityLevel associated with each session. Each unique combination of these parameters MUST have a locally-chosen unique tlstmSessionID for each active session. For further information see Section 5 (Elements of Procedure). TLS over TCP sessions, on the other hand, do not require a unique pairing of address and port attributes since their lower layer protocols (TCP) already provide adequate session framing. But they must still provide a unique tlstmSessionID for referencing the session.

The tlstmSessionID identifier MUST NOT change during the entire duration of the session from the TLSTM's perspective, and MUST uniquely identify a single session. As an implementation hint: note that the (D)TLS internal SessionID does not meet these requirements, since it can change over the life of the connection as seen by the TLSTM (for example, during renegotiation), and does not necessarily uniquely identify a TLSTM session (there can be multiple TLSTM sessions sharing the same D(TLS) internal SessionID).

3.2. Security Parameter Passing

For the (D)TLS server-side, (D)TLS-specific security parameters (i.e., cipher_suites, X.509 certificate fields, IP address and port) are translated by the TLS Transport Model into security parameters for the TLS Transport Model and security model (e.g., tmSecurityLevel, tmSecurityName, transportDomain, transportAddress). The transport-related and (D)TLS-security-related information, including the authenticated identity, are stored in a cache referenced by tmStateReference.

For the (D)TLS client-side, the TLS Transport Model takes input provided by the Dispatcher in the sendMessage() Abstract Service Interface (ASI) and input from the tmStateReference cache. The (D)TLS Transport Model converts that information into suitable security parameters for (D)TLS and establishes sessions as needed.

3.3. Notifications and Proxy

(D)TLS connections may be initiated by (D)TLS clients on behalf of SNMP appplications that initiate communications, such as command generators, notification originators, proxy forwarders. Command generators are frequently operated by a human, but notification originators and proxy forwarders are usually unmanned automated processes. The targets to whom notifications and proxied requests should be sent is typically determined and configured by a network administrator.

The SNMP-TARGET-MIB module [RFC3413] (Levi, D., Meyer, P., and B. Stewart, “Simple Network Management Protocol (SNMP) Applications,” December 2002.) contains objects for defining management targets, including transportDomain, transportAddress, securityName, securityModel, and securityLevel parameters, for notification originator, proxy forwarder, and SNMP-controllable command generator applications. Transport domains and transport addresses are configured in the snmpTargetAddrTable, and the securityModel, securityName, and securityLevel parameters are configured in the snmpTargetParamsTable. This document defines a MIB module that extends the SNMP-TARGET-MIB's snmpTargetParamsTable to specify a (D)TLS client-side certificate to use for the connection.

When configuring a (D)TLS target, the snmpTargetAddrTDomain and snmpTargetAddrTAddress parameters in snmpTargetAddrTable SHOULD be set to the snmpTLSTCPDomain or snmpDTLSUDPDomain object and an appropriate snmpTLSAddress value. When used with the SNMPv3 message processing model, the snmpTargetParamsMPModel column of the snmpTargetParamsTable SHOULD be set to a value of 3. The snmpTargetParamsSecurityName SHOULD be set to an appropriate securityName value and the snmpTlstmParamsClientFingerprint parameter of the snmpTlstmParamsTable SHOULD be set a value that refers to a locally held certificate (and the corresponding private key) to be used. Other parameters, for example cryptographic configuration such as which cipher suites to use, must come from configuration mechanisms not defined in this document.

The securityName defined in the snmpTargetParamsSecurityName column will be used by the access control model to authorize any notifications that need to be sent.

4. Elements of the Model

This section contains definitions required to realize the (D)TLS Transport Model defined by this document.

4.1. X.509 Certificates

(D)TLS can make use of X.509 certificates for authentication of both sides of the transport. This section discusses the use of X.509 certificates in the TLSTM.

While (D)TLS supports multiple authentication mechanisms, this document only discusses X.509 certificate based authentication; other forms of authentication are outside the scope of this specification. TLSTM implementations are REQUIRED to support X.509 certificates.

4.1.1. Provisioning for the Certificate

Authentication using (D)TLS will require that SNMP entities have certificates, either signed by trusted certification authorities, or self-signed. Furthermore, SNMP entities will most commonly need to be provisioned with root certificates which represent the list of trusted certificate authorities that an SNMP entity can use for certificate verification. SNMP entities SHOULD also be provisioned with a X.509 certificate revocation mechanism which can be used to verify that a certificate has not been revoked. Trusted public keys from either CA certificates and/or self-signed certificates MUST be installed into the server through a trusted out of band mechanism and their authenticity MUST be verified before access is granted.

Having received a certificate from a connecting TLSTM client, the authenticated tmSecurityName of the principal is derived using the snmpTlstmCertToTSNTable. This table allows mapping of incoming connections to tmSecurityNames through defined transformations. The transformations defined in the SNMP-TLS-TM-MIB include:

As an implementation hint: implementations may choose to discard any connections for which no potential snmpTlstmCertToTSNTable mapping exists before performing certificate verification to avoid expending computational resources associated with certificate verification.

Deployments SHOULD map the "subjectAltName" component of X.509 certificates to the TLSTM specific tmSecurityNames. The authenticated identity can be obtained by the TLS Transport Model by extracting the subjectAltName(s) from the peer's certificate. The receiving application will then have an appropriate tmSecurityName for use by other SNMPv3 components like an access control model.

The standard VACM access control model constrains securityNames to be 32 octets or less in length. A TLSTM generated tmSecurityName, possibly in combination with a messaging or security model that increases the length of the securityName, might cause the securityName length to exceed 32 octets. For example, a 32 octet tmSecurityName derived from an IPv6 address, paired with a TSM prefix, will generate a 36 octet securityName. Such a securityName will not be able to be used with standard VACM or TARGET MIB modules. Operators should be careful to select algorithms and subjectAltNames to avoid this situation.

A pictorial view of the complete transformation process (using the TSM security model for the example) is shown below:

4.2. (D)TLS Usage

TLSTM verifies the certificates when the connection is opened (see Section 5.3). For this reason, TLS renegotiation with different certificates MUST NOT be done. That is, implementations MUST either disable renegotiation completely (RECOMMENDED), or MUST present the same certificate during renegotiation (and MUST verify that the other end presented the same certificate).

For DTLS over UDP, each SNMP message MUST be placed in a single UDP datagram; it MAY be split to multiple DTLS records. In other words, if a single datagram contains multiple DTLS application_data records, they are concatenated when received. The TLSTM implementation SHOULD return an error if the SNMP message does not fit in the UDP datagram, and thus cannot be sent.

4.3. SNMP Services

This section describes the services provided by the TLS Transport Model with their inputs and outputs. The services are between the Transport Model and the Dispatcher.

The services are described as primitives of an abstract service interface (ASI) and the inputs and outputs are described as abstract data elements as they are passed in these abstract service primitives.

4.3.1. SNMP Services for an Outgoing Message

The Dispatcher passes the information to the TLS Transport Model using the ASI defined in the transport subsystem:

The abstract data elements returned from or passed as parameters into the abstract service primitives are as follows:

4.3.2. SNMP Services for an Incoming Message

The TLS Transport Model processes the received message from the network using the (D)TLS service and then passes it to the Dispatcher using the following ASI:

The abstract data elements returned from or passed as parameters into the abstract service primitives are as follows:

4.4. Cached Information and References

4.4.1. TLS Transport Model Cached Information

The TLS Transport Model has specific responsibilities regarding the cached information. See the Elements of Procedure in Section 5 (Elements of Procedure) for detailed processing instructions on the use of the tmStateReference fields by the TLS Transport Model.

4.4.1.1. tmSecurityName

The tmSecurityName MUST be a human-readable name (in snmpAdminString format) representing the identity that has been set according to the procedures in Section 5 (Elements of Procedure). The tmSecurityName MUST be constant for all traffic passing through a single TLSTM session. Messages MUST NOT be sent through an existing (D)TLS connection that was established using a different tmSecurityName.

On the (D)TLS server side of a connection the tmSecurityName is derived using the procedures described in Section 5.3.2 (Accepting a Session as a Server) and the SNMP-TLS-TM-MIB's snmpTlstmCertToTSNTable DESCRIPTION clause.

On the (D)TLS client side of a connection the tmSecurityName is presented to the TLS Transport Model by the application (possibly because of configuration specified in the SNMP-TARGET-MIB). The Security Model likely derived the tmSecurityName from the securityName presented to the Security Model by the application (possibly because of configuration specified in the SNMP-TARGET-MIB).

Transport-model-aware security models derive tmSecurityName from a securityName, possibly configured in MIB modules for notifications and access controls. Transport Models SHOULD use predictable tmSecurityNames so operators will know what to use when configuring MIB modules that use securityNames derived from tmSecurityNames. The TLSTM generates predictable tmSecurityNames based on the configuration found in the SNMP-TLS-TM-MIB's snmpTlstmCertToTSNTable and relies on the network operators to have configured this table appropriately.

4.4.1.2. tmSessionID

The tmSessionID MUST be recorded per message at the time of receipt. When tmSameSecurity is set, the recorded tmSessionID can be used to determine whether the (D)TLS connection available for sending a corresponding outgoing message is the same (D)TLS connection as was used when receiving the incoming message (e.g., a response to a request).

4.4.1.3. Session State

The per-session state that is referenced by tmStateReference may be saved across multiple messages in a Local Configuration Datastore. Additional session/connection state information might also be stored in a Local Configuration Datastore.

5. Elements of Procedure

To simplify the elements of procedure, the release of state information is not always explicitly specified. As a general rule, if state information is available when a message gets discarded, the message-state information should also be released. If state information is available when a session is closed, the session state information should also be released. Sensitive information, like cryptographic keys, should be overwritten appropriately prior to being released.

An error indication in statusInformation will typically include the Object Identifier (OID) and value for an incremented error counter. This may be accompanied by the requested securityLevel and the tmStateReference. Per-message context information is not accessible to Transport Models, so for the returned counter OID and value, contextEngine would be set to the local value of snmpEngineID and contextName to the default context for error counters.

5.1. Procedures for an Incoming Message

This section describes the procedures followed by the (D)TLS Transport Model when it receives a (D)TLS protected packet. The required functionality is broken into two different sections.

Section 5.1.1 (DTLS over UDP Processing for Incoming Messages) describes the processing required for de-multiplexing multiple DTLS connections, which is specifically needed for DTLS over UDP sessions. It is assumed that TLS protocol implementations already provide appropriate message demultiplexing.

5.1.1. DTLS over UDP Processing for Incoming Messages

Demultiplexing of incoming packets into separate DTLS sessions MUST be implemented. For connection-oriented transport protocols, such as TCP, the transport protocol takes care of demultiplexing incoming packets to the right connection. Depending on the DTLS implementation, for DTLS over UDP, this demultiplexing will either need to be done within the TLS implementation or by the TLSTM implementation.

Like TCP, DTLS over UDP uses the four-tuple <source IP, destination IP, source port, destination port> for identifying the connection (and relevant DTLS connection state). This means that when establishing a new session, implementations MUST use a different UDP source port number for each active connection to a remote destination IP-address/port-number combination to ensure the remote entity can disambiguate between multiple connections.

If demultiplexing received UDP datagrams to DTLS connection state is done by the TLSTM implementation (instead of the DTLS implementation), the steps below describe one possible method to accomplish this.

The important output results from the steps in this process are the remote transport address, incomingMessage, incomingMessageLength, and the tlstmSessionID.

5.1.2. Transport Processing for Incoming SNMP Messages

The procedures in this section describe how the TLS Transport Model should process messages that have already been properly extracted from the (D)TLS stream. Note that care must be taken when processing messages originating from either TLS or DTLS to ensure they're complete and single. For example, multiple SNMP messages can be passed through a single DTLS message and partial SNMP messages may be received from a TLS stream. These steps describe the processing of a singular SNMP message after it has been delivered from the (D)TLS stream.

5.2. Procedures for an Outgoing SNMP Message

The Dispatcher sends a message to the TLS Transport Model using the following ASI:

This section describes the procedure followed by the TLS Transport Model whenever it is requested through this ASI to send a message.

5.3. Establishing or Accepting a Session

Establishing a (D)TLS connection as either a client or a server requires slightly different processing. The following two sections describe the necessary processing steps.

5.3.1. Establishing a Session as a Client

The TLS Transport Model provides the following primitive for use by a client to establish a new (D)TLS connection:

The following describes the procedure to follow when establishing a SNMP over (D)TLS connection between SNMP engines for exchanging SNMP messages. This process is followed by any SNMP client's engine when establishing a session for subsequent use.

This procedure MAY be done automatically for an SNMP application that initiates a transaction, such as a command generator, a notification originator, or a proxy forwarder.

5.3.2. Accepting a Session as a Server

The (D)TLS server identifies the authenticated identity from the (D)TLS client's principal certificate using configuration information from the snmpTlstmCertToTSNTable mapping table. The (D)TLS server MUST request and expect a certificate from the client and MUST NOT accept SNMP messages over the (D)TLS connection until the client has sent a certificate and it has been authenticated. The resulting derived tmSecurityName is recorded in the tmStateReference cache as tmSecurityName. The details of the lookup process are fully described in the DESCRIPTION clause of the snmpTlstmCertToTSNTable MIB object. If any verification fails in any way (for example because of failures in cryptographic verification or because of the lack of an appropriate row in the snmpTlstmCertToTSNTable) then the session establishment MUST fail, and the snmpTlstmSessionInvalidClientCertificates object is incremented. If the session can not be opened for any reason at all, including cryptographic verification failures, then the snmpTlstmSessionOpenErrors counter is incremented and processing stops.

5.4. Closing a Session

The following describes the procedure to follow to close a session between a client and server. This process is followed by any SNMP engine closing the corresponding SNMP session.

6. MIB Module Overview

This MIB module provides management of the TLS Transport Model. It defines needed textual conventions, statistical counters, notifications and configuration infrastructure necessary for session establishment. Example usage of the configuration tables can be found in Appendix A (Target and Notification Configuration Example).

6.1. Structure of the MIB Module

Objects in this MIB module are arranged into subtrees. Each subtree is organized as a set of related objects. The overall structure and assignment of objects to their subtrees, and the intended purpose of each subtree, is shown below.

6.2. Textual Conventions

Generic and Common Textual Conventions used in this module can be found summarized at http://www.ops.ietf.org/mib-common-tcs.html

6.3. Statistical Counters

The SNMP-TLS-TM-MIB defines counters that provide network management stations with information about session usage and potential errors that a device may be experiencing.

6.4. Configuration Tables

The SNMP-TLS-TM-MIB defines configuration tables that an administrator can use for configuring a device for sending and receiving SNMP messages over (D)TLS. In particular, there are MIB tables that extend the SNMP-TARGET-MIB for configuring (D)TLS certificate usage and a MIB table for mapping incoming (D)TLS client certificates to SNMPv3 securityNames.

6.4.1. Notifications

The SNMP-TLS-TM-MIB defines notifications to alert management stations when a (D)TLS connection fails because a server's presented certificate did not meet an expected value (snmpTlstmServerCertificateUnknown) or because cryptographic validation failed (snmpTlstmServerInvalidCertificate).

6.5. Relationship to Other MIB Modules

The SNMP-TLS-TM-MIB module contained in this document is for managing TLS Transport Model information.

6.5.1. MIB Modules Required for IMPORTS

7. MIB Module Definition

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

IMPORTS
    MODULE-IDENTITY, OBJECT-TYPE,
    OBJECT-IDENTITY, mib-2, snmpDomains,
    Counter32, Unsigned32, Gauge32, NOTIFICATION-TYPE
      FROM SNMPv2-SMI                   -- RFC2578 or any update thereof
    TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType,
    AutonomousType
      FROM SNMPv2-TC                    -- RFC2579 or any update thereof
    MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
      FROM SNMPv2-CONF                  -- RFC2580 or any update thereof
    SnmpAdminString
      FROM SNMP-FRAMEWORK-MIB           -- RFC3411 or any update thereof
    snmpTargetParamsName, snmpTargetAddrName
      FROM SNMP-TARGET-MIB              -- RFC3413 or any update thereof
    ;

snmpTlstmMIB MODULE-IDENTITY
    LAST-UPDATED "201005070000Z"
    ORGANIZATION "ISMS Working Group"
    CONTACT-INFO "WG-EMail:   isms@lists.ietf.org
                  Subscribe:  isms-request@lists.ietf.org

                  Chairs:
                     Juergen Schoenwaelder
                     Jacobs University Bremen
                     Campus Ring 1
                     28725 Bremen
                     Germany
                     +49 421 200-3587
                     j.schoenwaelder@jacobs-university.de

                     Russ Mundy
                     SPARTA, Inc.
                     7110 Samuel Morse Drive
                     Columbia, MD  21046
                     USA

                  Editor:
                     Wes Hardaker
                     Sparta, Inc.
                     P.O. Box 382
                     Davis, CA  95617
                     USA
                     ietf@hardakers.net
                  "

    DESCRIPTION  "
        The TLS Transport Model MIB

        Copyright (c) 2010 IETF Trust and the persons identified as
        the document authors.  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 Simplified BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info)."

       REVISION     "201005070000Z"
       DESCRIPTION  "This version of this MIB module is part of
                     RFC XXXX; see the RFC itself for full legal
                     notices."

-- NOTE to RFC editor: replace XXXX with actual RFC number
--                     for this document and change the date to the
--                     current date and remove this note

    ::= { mib-2 www }
-- RFC Ed.: replace www with IANA-assigned number under the mib-2
--          SNMP OID tree and remove this note

-- ************************************************
-- 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 }

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

snmpTLSTCPDomain OBJECT-IDENTITY
    STATUS      current
    DESCRIPTION
        "The SNMP over TLS 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
      "RFC 2579: Textual Conventions for SMIv2"

    ::= { snmpDomains xx }


-- RFC Ed.: replace xx with IANA-assigned number and
--          remove this note

-- RFC Ed.: replace 'tls' with the actual IANA assigned prefix string
--          if 'tls' is not assigned to this document.

snmpDTLSUDPDomain OBJECT-IDENTITY
    STATUS      current
    DESCRIPTION
        "The SNMP over DTLS/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
      "RFC 2579: Textual Conventions for SMIv2"

    ::= { snmpDomains yy }


-- RFC Ed.: replace yy with IANA-assigned number and
--          remove this note

-- RFC Ed.: replace 'dtls' with the actual IANA assigned prefix string
--          if 'dtls' is not assigned to this document.

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

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

        An IPv6 address must be a colon separated format (as described
        in I-D.ietf-6man-text-addr-representation), surrounded by
        square brackets ('[', US-ASCII character 0x5B, and ']',
        US-ASCII character 0x5D), followed by a colon ':' (US-ASCII
        character 0x3A) and a decimal port number in US-ASCII.

        A hostname is always in US-ASCII (as per RFC1033);
        internationalized hostnames are encoded in US-ASCII as domain
        names after transformation via the ToASCII operation specified
        in RFC 3490.  The ToASCII operation MUST be performed with the
        UseSTD3ASCIIRules flag set.  The hostname is followed by a
        colon ':' (US-ASCII character 0x3A) and a decimal port number
        in US-ASCII.  The name SHOULD be fully qualified whenever
        possible.

        Values of this textual convention may not be directly usable
        as transport-layer addressing information, and may require
        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 either by
        including SIZE constraints on the index components or by
        specifying applicable constraints in the conceptual row
        DESCRIPTION clause or in the surrounding documentation."
    REFERENCE
      "RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE
       RFC 3490: Internationalizing Domain Names in Applications
       I-D.ietf-6man-text-addr-representation:
           A Recommendation for IPv6 Address Text Representation
      "
    SYNTAX       OCTET STRING (SIZE (1..255))

-- RFC Editor: if I-D.ietf-6man-text-addr-representation fails to get
-- published then replace the reference to
-- I-D.ietf-6man-text-addr-representation with a reference to
-- "RFC3513: Internet Protocol Version 6 (IPv6) Addressing Architecture"
-- instead.

SnmpTLSFingerprint ::= TEXTUAL-CONVENTION
    DISPLAY-HINT "1x:254x"
    STATUS       current
    DESCRIPTION
       "A fingerprint value that can be used to uniquely reference
       other data of potentially arbitrary length.

       A SnmpTLSFingerprint value is composed of a 1-octet hashing
       algorithm identifier followed by the fingerprint value.  The
       octet value encoded is taken from the IANA TLS HashAlgorithm
       Registry (RFC5246).  The remaining octets are filled using the
       results of the hashing algorithm.

       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
                  http://www.iana.org/assignments/tls-parameters/
       "
       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 host-part of the name must
                  be passed in lower case.  This mapping results in a
                  1:1 correspondence between equivalent subjectAltName
                  rfc822Name values and tmSecurityName values except
                  that the host-part of the name MUST be passed in
                  lower case.

                  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
                  lower case (RFC5280 does not specify converting to
                  lower case so this involves an extra step).  This
                  mapping results in a 1:1 correspondence between
                  subjectAltName dNSName values and the tmSecurityName
                  values."
    REFERENCE "RFC5280 - 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 is the maximum length supported
                  by the View-Based Access Control Model (VACM).
                  Using both the Transport Security Model's support
                  for transport prefixes (see the SNMP-TSM-MIB's
                  snmpTsmConfigurationUsePrefix object for details)
                  will result in securityName lengths that exceed what
                  VACM can handle."
    ::= { 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 matching subjectAltName value found in the
                  certificate of the above types MUST be used when
                  deriving the tmSecurityName.  The mapping algorithm
                  specified in the 'Algorithm' column 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 an (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 an (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 an (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 was 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 an (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 an (D)TLS client because the server certificate presented
         by a SNMP over (D)TLS server was invalid because no
         configured fingerprint or CA was acceptable to validate it.
         This may result because there was no entry in the
         snmpTlstmAddrTable or because no path could be found to a
         known certification authority."
    ::= { 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 an (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.  I.E.,
         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 must either be validated based on an established
        trust anchor, or it 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 by path
        validation or 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 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 looking 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., 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 looking 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 (E.G., 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 so
        that a single root CA certificate can allow all child
        certificate's subjectAltName to map 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 a X.509 certificate.  The results of
        a successful matching fingerprint to either the trusted CA in
        the certificate validation path or to 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 model and
        processing stops.

        If the resulting mapped value is not compatible with the
        needed requirements of a tmSecurityName (e.g., 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 data 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 may 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 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 may 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 a certificate fingerprint, or 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 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 [RFC5280] 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 common
            name, if used to store the host name), but only as the
            left-most (least significant) DNS label in that value.
            This wildcard matches any left-most 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 [RFC5280].

          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 a snmpTargetAddrEntry row then the connection
        SHOULD still proceed if some other certificate validation path
        algorithm (e.g. RFC5280) 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 may 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 a 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 could be found to known certificate
         authority.

         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.  I.E., 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 which
        implements the SNMP TLS Transport Model."
    ::= { 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 which implements the
        SNMP TLS Transport Model."
    ::= { 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

8. Operational Considerations

8.1. Sessions

A session is discussed throughout this document as meaning a security association between two TLSTM instances. State information for the sessions are maintained in each TLSTM implementation and this information is created and destroyed as sessions are opened and closed. A "broken" session (one side up and one side down) can result if one side of a session is brought down abruptly (i.e., reboot, power outage, etc.). Whenever possible, implementations SHOULD provide graceful session termination through the use of TLS disconnect messages. Implementations SHOULD also have a system in place for detecting "broken" sessions through the use of heartbeats [I‑D.seggelmann‑tls‑dtls‑heartbeat] (Seggelmann, R., Tuexen, M., and M. Williams, “Transport Layer Security and Datagram Transport Layer Security Heartbeat Extension,” .) or other detection mechanisms.

Implementations SHOULD limit the lifetime of established sessions depending on the algorithms used for generation of the master session secret, the privacy and integrity algorithms used to protect messages, the environment of the session, the amount of data transferred, and the sensitivity of the data.

8.2. Notification Receiver Credential Selection

When an SNMP engine needs to establish an outgoing session for notifications, the snmpTargetParamsTable includes an entry for the snmpTargetParamsSecurityName of the target. Servers that wish to support multiple principals at a particular port SHOULD make use of the Server Name Indication extension defined in Section 3.1 of [RFC4366] (Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., and T. Wright, “Transport Layer Security (TLS) Extensions,” April 2006.). Without the Server Name Indication the receiving SNMP engine (Server) will not know which (D)TLS certificate to offer to the Client so that the tmSecurityName identity-authentication will be successful.

Another solution is to maintain a one-to-one mapping between certificates and incoming ports for notification receivers. This can be handled at the notification originator by configuring the snmpTargetAddrTable (snmpTargetAddrTDomain and snmpTargetAddrTAddress) and requiring the receiving SNMP engine to monitor multiple incoming static ports based on which principals are capable of receiving notifications.

Implementations MAY also choose to designate a single Notification Receiver Principal to receive all incoming notifications or select an implementation specific method of selecting a server certificate to present to clients.

8.3. contextEngineID Discovery

SNMPv3 requires that an application know the identifier (snmpEngineID) of the remote SNMP protocol engine in order to retrieve or manipulate objects maintained on the remote SNMP entity.

8.4. Transport Considerations

This document defines how SNMP messages can be transmitted over the TLS and DTLS based protocols. Each of these protocols are additionally based on other transports (TCP and UDP). These two base protocols also have operational considerations that must be taken into consideration when selecting a (D)TLS based protocol to use such as its performance in degraded or limited networks. It is beyond the scope of this document to summarize the characteristics of these transport mechanisms. Please refer to the base protocol documents for details on messaging considerations with respect to MTU size, fragmentation, performance in lossy-networks, etc.

9. Security Considerations

9.1. Certificates, Authentication, and Authorization

Implementations are responsible for providing a security certificate installation and configuration mechanism. Implementations SHOULD support certificate revocation lists.

(D)TLS provides for authentication of the identity of both the (D)TLS server and the (D)TLS client. Access to MIB objects for the authenticated principal MUST be enforced by an access control subsystem (e.g. the VACM).

Authentication of the command generator principal's identity is important for use with the SNMP access control subsystem to ensure that only authorized principals have access to potentially sensitive data. The authenticated identity of the command generator principal's certificate is mapped to an SNMP model-independent securityName for use with SNMP access control.

The (D)TLS handshake only provides assurance that the certificate of the authenticated identity has been signed by an configured accepted certification authority. (D)TLS has no way to further authorize or reject access based on the authenticated identity. An Access Control Model (such as the VACM) provides access control and authorization of a command generator's requests to a command responder and a notification receiver's authorization to receive Notifications from a notification originator. However to avoid man-in-the-middle attacks both ends of the (D)TLS based connection MUST check the certificate presented by the other side against what was expected. For example, command generators must check that the command responder presented and authenticated itself with a X.509 certificate that was expected. Not doing so would allow an impostor, at a minimum, to present false data, receive sensitive information and/or provide a false belief that configuration was actually received and acted upon. Authenticating and verifying the identity of the (D)TLS server and the (D)TLS client for all operations ensures the authenticity of the SNMP engine that provides MIB data.

The instructions found in the DESCRIPTION clause of the snmpTlstmCertToTSNTable object must be followed exactly. It is also important that the rows of the table be searched in prioritized order starting with the row containing the lowest numbered snmpTlstmCertToTSNID value.

9.2. (D)TLS Security Considerations

9.2.1. TLS Version Requirements

9.2.2. Perfect Forward Secrecy

9.3. Use with SNMPv1/SNMPv2c Messages

The SNMPv1 and SNMPv2c message processing described in [RFC3584] (Frye, R., Levi, D., Routhier, S., and B. Wijnen, “Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework,” August 2003.) (BCP 74) always selects the SNMPv1 or SNMPv2c Security Models, respectively. Both of these and the User-based Security Model typically used with SNMPv3 derive the securityName and securityLevel from the SNMP message received, even when the message was received over a secure transport. Access control decisions are therefore made based on the contents of the SNMP message, rather than using the authenticated identity and securityLevel provided by the TLS Transport Model. 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.

9.4. MIB Module Security

There are a number of management objects defined in this MIB module with a MAX-ACCESS clause of read-write and/or read-create. Such objects may be considered sensitive or vulnerable in some network environments. The support for SET operations in a non-secure environment without proper protection can have a negative effect on network operations. These are the tables and objects and their sensitivity/vulnerability:

Some of the readable objects in this MIB module (i.e., objects with a MAX-ACCESS other than not-accessible) may be considered sensitive or vulnerable in some network environments. It is thus important to control even GET and/or NOTIFY access to these objects and possibly to even encrypt the values of these objects when sending them over the network via SNMP. These are the tables and objects and their sensitivity/vulnerability:

SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example by using IPsec), even then, 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.

Further, deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to enable cryptographic security. It is then a customer/operator responsibility to ensure that the SNMP entity giving access to an instance of this MIB module is properly configured to give access to the objects only to those principals (users) that have legitimate rights to indeed GET or SET (change/create/delete) them.

10. IANA Considerations

RFC Editor's note: this section should be replaced with appropriate descriptive assignment text after IANA assignments are made and prior to publication.

11. Acknowledgements

This document was reviewed by the following people who helped provide useful comments (in alphabetical order): Andy Donati, Pasi Eronen, David Harrington, Jeffrey Hutzelman, Alan Luchuk, Michael Peck, Tom Petch, Randy Presuhn, Ray Purvis, Peter Saint-Andre, Joseph Salowey, Jurgen Schonwalder, Dave Shield, Robert Story.

This work was supported in part by the United States Department of Defense. Large portions of this document are based on work by General Dynamics C4 Systems and the following individuals: Brian Baril, Kim Bryant, Dana Deluca, Dan Hanson, Tim Huemiller, John Holzhauer, Colin Hoogeboom, Dave Kornbau, Chris Knaian, Dan Knaul, Charles Limoges, Steve Moccaldi, Gerardo Orlando, and Brandon Yip.

12. References

12.1. Normative References

12.2. Informative References

Appendix A. Target and Notification Configuration Example

The following sections describe example configuration for the SNMP-TLS-TM-MIB, the SNMP-TARGET-MIB, the NOTIFICATION-MIB and the SNMP-VIEW-BASED-ACM-MIB.

A.1. Configuring a Notification Originator

The following row configures the snmpTlstmAddrTable to use certificate path validation and to require the remote notification receiver to present a certificate for the "server.example.org" identity.

The following row configures the snmpTargetAddrTable to send notifications using TLS/TCP to the snmptls-trap port at 192.0.2.1:

RFC Editor's note: replace the string "XXXsnmptls-trap" above with the appropriately assigned "snmptls-trap" port.

The following row configures the snmpTargetParamsTable to send the notifications to "Joe Cool", using authPriv SNMPv3 notifications through the TransportSecurityModel [RFC5591]:

A.2. Configuring TLSTM to Utilize a Simple Derivation of tmSecurityName

The following row configures the snmpTlstmCertToTSNTable to map a validated client certificate, referenced by the client's public X.509 hash fingerprint, to a tmSecurityName using the subjectAltName component of the certificate.

This type of configuration should only be used when the naming conventions of the (possibly multiple) certificate authorities are well understood, so two different principals cannot inadvertently be identified by the same derived tmSecurityName.

A.3. Configuring TLSTM to Utilize Table-Driven Certificate Mapping

The following row configures the snmpTlstmCertToTSNTable to map a validated client certificate, referenced by the client's public X.509 hash fingerprint, to the directly specified tmSecurityName of "Joe Cool".

[RFC1033]	Lottor, M., “Domain administrators operations guide,” RFC 1033, November 1987 (TXT).
[RFC2119]	Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997 (TXT, HTML, XML).
[RFC2578]	McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., “Structure of Management Information Version 2 (SMIv2),” STD 58, RFC 2578, April 1999 (TXT).
[RFC2579]	McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., “Textual Conventions for SMIv2,” STD 58, RFC 2579, April 1999 (TXT).
[RFC2580]	McCloghrie, K., Perkins, D., and J. Schoenwaelder, “Conformance Statements for SMIv2,” STD 58, RFC 2580, April 1999 (TXT).
[RFC3411]	Harrington, D., Presuhn, R., and B. Wijnen, “An Architecture for Describing Simple Network Management Protocol (SNMP) Management Frameworks,” STD 62, RFC 3411, December 2002 (TXT).
[RFC3413]	Levi, D., Meyer, P., and B. Stewart, “Simple Network Management Protocol (SNMP) Applications,” STD 62, RFC 3413, December 2002 (TXT).
[RFC3414]	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 (TXT).
[RFC3415]	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 (TXT).
[RFC3418]	Presuhn, R., “Management Information Base (MIB) for the Simple Network Management Protocol (SNMP),” STD 62, RFC 3418, December 2002 (TXT).
[RFC3490]	Faltstrom, P., Hoffman, P., and A. Costello, “Internationalizing Domain Names in Applications (IDNA),” RFC 3490, March 2003 (TXT).
[RFC3584]	Frye, R., Levi, D., Routhier, S., and B. Wijnen, “Coexistence between Version 1, Version 2, and Version 3 of the Internet-standard Network Management Framework,” BCP 74, RFC 3584, August 2003 (TXT).
[RFC4347]	Rescorla, E. and N. Modadugu, “Datagram Transport Layer Security,” RFC 4347, April 2006 (TXT).
[RFC4366]	Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., and T. Wright, “Transport Layer Security (TLS) Extensions,” RFC 4366, April 2006 (TXT).
[RFC5246]	Dierks, T. and E. Rescorla, “The Transport Layer Security (TLS) Protocol Version 1.2,” RFC 5246, August 2008 (TXT).
[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, May 2008 (TXT).
[RFC5590]	Harrington, D. and J. Schoenwaelder, “Transport Subsystem for the Simple Network Management Protocol (SNMP),” RFC 5590, June 2009 (TXT).
[RFC5591]	Harrington, D. and W. Hardaker, “Transport Security Model for the Simple Network Management Protocol (SNMP),” RFC 5591, June 2009 (TXT).
[I-D.draft-ietf-6man-text-addr-representation]	Kawamura, S. and M. Kawashima, “A Recommendation for IPv6 Address Text Representation.”

[RFC3410]	Case, J., Mundy, R., Partain, D., and B. Stewart, “Introduction and Applicability Statements for Internet-Standard Management Framework,” RFC 3410, December 2002 (TXT).
[RFC5343]	Schoenwaelder, J., “Simple Network Management Protocol (SNMP) Context EngineID Discovery,” RFC 5343, September 2008 (TXT).
[RFC5592]	Harrington, D., Salowey, J., and W. Hardaker, “Secure Shell Transport Model for the Simple Network Management Protocol (SNMP),” RFC 5592, June 2009 (TXT).
[I-D.seggelmann-tls-dtls-heartbeat]	Seggelmann, R., Tuexen, M., and M. Williams, “Transport Layer Security and Datagram Transport Layer Security Heartbeat Extension.”

	Wes Hardaker
	Sparta, Inc.
	P.O. Box 382
	Davis, CA 95617
	USA
Phone:	+1 530 792 1913
Email:	ietf@hardakers.net

Transport Layer Security (TLS) Transport Model for the Simple Network Management Protocol (SNMP)draft-ietf-isms-dtls-tm-14.txt

Abstract