Network Working Group A. Bierman
Internet-Draft YumaWorks
Intended status: Standards Track M. Bjorklund
Expires: October 24, 2013 Tail-f Systems
April 22, 2013

YANG Data Model for System Management
draft-ietf-netmod-system-mgmt-06

Abstract

This document defines a YANG data model for the configuration and identification of the management system of a device.

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."

This Internet-Draft will expire on October 24, 2013.

Copyright Notice

Copyright (c) 2013 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

This document defines a YANG [RFC6020] data model for the configuration and identification of some common properties within the management system of a device.

Devices that are managed by NETCONF and perhaps other mechanisms have common properties that need to be configured and monitored in a standard way.

The "ietf‑system" YANG module defined in this document provides the following features:

1.1. Terminology

The keywords "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].

1.1.1. Terms

The following terms are used within this document:

1.2. Tree Diagrams

A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is as follows:

2. Objectives

2.1. System Identification

There are many common properties used to identify devices, operating systems, software versions, etc. that need to be supported in the system data module. These objects are defined as operational data and the information returned by the server is intended to be specific to the device vendor.

Some user-configurable administrative strings are also provided, such as the system location and description.

2.2. System Time Management

The management of the date and time used by the system need to be supported. Use of one or more NTP servers to automatically set the system date and time need to be possible. Utilization of the Timezone database [RFC6557] also need to be supported. It should be possible for the server, as well as clients, to configure the system to use NTP.

2.3. User Authentication

The authentication mechanism need to support password authentication over RADIUS, to support deployment scenarios with centralized authentication servers. Additionally, local users need to be supported, for scenarios when no centralized authentication server exists, or for situations where the centralized authentication server cannot be reached from the device.

Since the mandatory transport protocol for NETCONF is SSH [RFC6242] the authentication model need to support SSH's "publickey" and "password" authentication methods [RFC4252].

The model for authentication configuration should be flexible enough to support authentication methods defined by other standard documents or by vendors. It should be possible for the server, as well as clients, to configure the system authentication properties.

3. System Data Model

3.1. System Identification

The data model for system identification has the following structure:

   +--rw system
      +--rw contact?          string
      +--rw hostname?         inet:domain-name
      +--rw location?         string
      +--ro platform
         +--ro os-name?       string
         +--ro os-release?    string
         +--ro os-version?    string
         +--ro machine?       string
	    

3.2. System Time Management

The data model for system time management has the following structure:

   +--rw system
      +--rw clock
      |  +--ro current-datetime?      yang:date-and-time
      |  +--ro boot-datetime?         yang:date-and-time
      |  +--rw (timezone)?
      |     +--:(timezone-location)
      |     |  +--rw timezone-location?     string
      |     +--:(timezone-utc-offset)
      |        +--rw timezone-utc-offset?   int16
      +--rw ntp
         +--rw enabled?      boolean
         +--rw server [address]
            +--rw association-type? enumeration
            +--rw address    inet:host
            +--rw enabled?   boolean
            +--rw iburst?    boolean
            +--rw prefer?    boolean
	    

3.3. DNS Resolver Model

The data model for configuration of the DNS resolver has the following structure:

   +--rw system
      +--rw dns
         +--rw search*    inet:domain-name
         +--rw server*    inet:ip-address
         +--rw options
            +--rw timeout?    uint8
            +--rw attempts?   uint8
	    

3.4. RADIUS Client Model

The data model for configuration of the RADIUS client has the following structure:

   +--rw system
      +--rw radius
         +--rw server [address]
         |  +--rw address     inet:host
         |  +--rw (transport)
         |  |  +--:(udp)
         |  |     +--rw udp
         |  |        +--rw authentication-port?   inet:port-number
         |  |        +--rw shared-secret          string
         |  +--rw authentication-type?   identityref
         +--rw options
            +--rw timeout?    uint8
            +--rw attempts?   uint8
	    

3.5. User Authentication Model

This document defines three authentication methods for use with NETCONF:

Additional methods can be defined by other standard documents or by vendors.

This document defines two optional YANG features, "local‑users" and "radius‑authentication", which the server advertises to indicate support for configuring local users on the device, and support for using RADIUS for authentication, respectively.

The authentication parameters defined in this document are primarily used to configure authentication of NETCONF users, but MAY also be used by other interfaces, e.g., a Command Line Interface or a Web-based User Interface.

The data model for user authentication has the following structure:

   +--rw system
      +--rw authentication
         +--rw user-authentication-order*   identityref
         +--rw user [name]
            +--rw name        string
            +--rw password?   crypt-hash
            +--rw ssh-key [name]
               +--rw name         string
               +--rw algorithm?   string
               +--rw key-data?    binary
	    

3.5.1. SSH Public Key Authentication

If the NETCONF server advertises the "local‑users" feature, configuration of local users and their SSH public keys is supported in the /system/authentication/user list.

Public key authentication is requested by the SSH client. If the "local‑users" feature is supported, then when a NETCONF client starts an SSH session towards the server using the "publickey" authentication "method name" [RFC4252], the SSH server looks up the user name given in the SSH authentication request in the /system/authentication/user list, and verifies the key as described in [RFC4253].

3.5.2. Local User Password Authentication

If the NETCONF server advertises the "local‑users" feature, configuration of local users and their passwords is supported in the /system/authentication/user list.

For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if local user password authentication should be used.

In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.

When local user password authentication is requested, the NETCONF transport looks up the user name provided by the client in the /system/ authentication/user list, and verifies the password.

3.5.3. RADIUS Password Authentication

If the NETCONF server advertises the "radius‑authentication" feature, the device supports user authentication using RADIUS.

For NETCONF transport protocols that support password authentication, the leaf-list "user‑authentication‑order" is used to control if RADIUS password authentication should be used.

In SSH, password authentication is requested by the client. Other NETCONF transport protocols MAY also support password authentication.

3.6. System Control

Two protocol operations are included to restart or shutdown the system. The 'system‑restart' operation can be used to restart the entire system (not just the NETCONF server). The 'system‑shutdown' operation can be used to power off the entire system.

4. System YANG module

This YANG module imports YANG extensions from [RFC6536], and imports YANG types from [I-D.ietf-netmod-rfc6021-bis] and [I-D.ietf-netmod-iana-timezones]. It also references [RFC1321], [RFC2865], [RFC3418], [RFC5607], [IEEE-1003.1-2008], and [FIPS.180-3.2008].

RFC Ed.: update the date below with the date of RFC publication and remove this note.

<CODE BEGINS> file "ietf-system@2013-04-21.yang"

module ietf-system {
  namespace "urn:ietf:params:xml:ns:yang:ietf-system";
  prefix "sys";

  import ietf-yang-types {
    prefix yang;
  }

  import ietf-inet-types {
    prefix inet;
  }

  import ietf-netconf-acm {
    prefix nacm;
  }

  import iana-timezones {
    prefix ianatz;
  }

  organization
    "IETF NETMOD (NETCONF Data Modeling Language) Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

     WG Chair: David Kessens
               <mailto:david.kessens@nsn.com>

     WG Chair: Juergen Schoenwaelder
               <mailto:j.schoenwaelder@jacobs-university.de>

     Editor:   Andy Bierman
               <mailto:andy@yumaworks.com>

     Editor:   Martin Bjorklund
               <mailto:mbj@tail-f.com>";

  description
    "This module contains a collection of YANG definitions for the
     configuration and identification of the management system of a
     device.

     Copyright (c) 2013 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 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).

     This version of this YANG module is part of RFC XXXX; see
     the RFC itself for full legal notices.";

  // RFC Ed.: replace XXXX with actual RFC number and remove this
  // note.

  // RFC Ed.: remove this note
  // Note: extracted from draft-ietf-netmod-system-mgmt-06.txt

  // RFC Ed.: update the date below with the date of RFC publication
  // and remove this note.
  revision "2013-04-21" {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for System Management";
  }

  /*
   * Typedefs
   */

  typedef crypt-hash {
    type string {
      pattern
        '$0$.*'
      + '|$1$[a-zA-Z0-9./]{1,8}$[a-zA-Z0-9./]{22}'
      + '|$5$(rounds=\d+$)?[a-zA-Z0-9./]{1,16}$[a-zA-Z0-9./]{43}'
      + '|$6$(rounds=\d+$)?[a-zA-Z0-9./]{1,16}$[a-zA-Z0-9./]{86}';
    }
    description
      "The crypt-hash type is used to store passwords using
       a hash function.  The algorithms for applying the hash
       function and encoding the result are implemented in
       various UNIX systems as the function crypt(3).

       A value of this type matches one of the forms:

         $0$<clear text password>
         $<id>$<salt>$<password hash>
         $<id>$<parameter>$<salt>$<password hash>

       The '$0$' prefix signals that the value is clear text.  When
       such a value is received by the server, a hash value is
       calculated, and the string '$<id>$<salt>$' or
       $<id>$<parameter>$<salt>$ is prepended to the result.  This
       value is stored in the configuration data store.

       If a value starting with '$<id>$', where <id> is not '0', is
       received, the server knows that the value already represents a
       hashed value, and stores it as is in the data store.

       When a server needs to verify a password given by a user, it
       finds the stored password hash string for that user, extracts
       the salt, and calculates the hash with the salt and given
       password as input.  If the calculated hash value is the same
       as the stored value, the password given by the client is
       correct.

       This type defines the following hash functions:

         id | hash function | feature
         ---+---------------+-------------------
          1 | MD5           | crypt-hash-md5
          5 | SHA-256       | crypt-hash-sha-256
          6 | SHA-512       | crypt-hash-sha-512

       The server indicates support for the different hash functions
       by advertising the corresponding feature.";
    reference
      "IEEE Std 1003.1-2008 - crypt() function
       Wikipedia: http://en.wikipedia.org/wiki/Crypt_(C)
       RFC 1321: The MD5 Message-Digest Algorithm
       FIPS.180-3.2008: Secure Hash Standard";
  }

  /*
   * Features
   */

  feature radius {
    description
      "Indicates that the device can be configured as a RADIUS
       client.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service "
    + "(RADIUS)";
  }

  feature authentication {
    description
      "Indicates that the device can be configured
       to do authentication of users.";
  }

  feature local-users {
    if-feature authentication;
    description
      "Indicates that the device supports
       local user authentication.";
  }

  feature radius-authentication {
    if-feature radius;
    if-feature authentication;
    description
      "Indicates that the device supports user authentication over
       RADIUS.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service (RADIUS)
       RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
                 Authorization for Network Access Server (NAS)
                 Management";
  }

  feature crypt-hash-md5 {
    description
      "Indicates that the device supports the MD5
       hash function in 'crypt-hash' values";
    reference "RFC 1321: The MD5 Message-Digest Algorithm";
  }

  feature crypt-hash-sha-256 {
    description
      "Indicates that the device supports the SHA-256
       hash function in 'crypt-hash' values";
    reference "FIPS.180-3.2008: Secure Hash Standard";
  }

  feature crypt-hash-sha-512 {
    description
      "Indicates that the device supports the SHA-512
       hash function in 'crypt-hash' values";
    reference "FIPS.180-3.2008: Secure Hash Standard";
  }

  feature ntp {
    description
      "Indicates that the device can be configured
       to use one or more NTP servers to set the
       system date and time.";
  }

  feature timezone-location {
    description
      "Indicates that the local timezone on the device
       can be configured to use the TZ database
       to set the timezone and manage daylight savings time.";
    reference
      "TZ Database  http://www.twinsun.com/tz/tz-link.htm
       Maintaining the Timezone Database
         RFC 6557 (BCP 175)";
  }

  /*
   * Identities
   */

  identity authentication-method {
    description
      "Base identity for user authentication methods.";
  }

  identity radius {
    base authentication-method;
    description
      "Indicates user authentication using RADIUS.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service (RADIUS)
       RFC 5607: Remote Authentication Dial-In User Service (RADIUS)
                 Authorization for Network Access Server (NAS)
                 Management";
  }

  identity local-users {
    base authentication-method;
    description
      "Indicates password-based authentication of locally
       configured users.";
  }

  identity radius-authentication-type {
    description
      "Base identity for RADIUS authentication types.";
  }

  identity radius-pap {
    base radius-authentication-type;
    description
      "The device requests PAP authentication from the RADIUS
       server.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service";
  }

  identity radius-chap {
    base radius-authentication-type;
    description
      "The device requests CHAP authentication from the RADIUS
       server.";
    reference
      "RFC 2865: Remote Authentication Dial In User Service";
  }

  /*
   * Top-level container
   */

  container system {
    description
      "System group configuration.";

    leaf contact {
      type string {
        length "0..255";
      }
      description
        "The administrator contact information for the system.";
      reference
        "RFC 3418 - Management Information Base (MIB) for the
                    Simple Network Management Protocol (SNMP)
                    SNMPv2-MIB.sysContact";
    }

    leaf hostname {
      type inet:domain-name;
     description
       "The name of the host.  This name can be a single domain
        label, or the fully qualified domain name of the host.";
    }

    leaf location {
      type string {
        length "0..255";
      }
      description
        "The system location.";
      reference
        "RFC 3418 - Management Information Base (MIB) for the
                    Simple Network Management Protocol (SNMP)
                    SNMPv2-MIB.sysLocation";
    }

    container platform {
      config false;
      description
        "Contains vendor-specific information for
         identifying the system platform and operating system.";
      reference
        "IEEE Std 1003.1-2008 - sys/utsname.h";

      leaf os-name {
        type string;
        description
          "The name of the operating system in use,
           for example 'Linux'";
        reference
          "IEEE Std 1003.1-2008 - utsname.sysname";
      }

      leaf os-release {
        type string;
        description
          "The current release level of the operating
           system in use.  This string MAY indicate
           the OS source code revision.";
        reference
          "IEEE Std 1003.1-2008 - utsname.release";
      }

      leaf os-version {
        type string;
        description
          "The current version level of the operating
           system in use.  This string MAY indicate
           the specific OS build date and target variant
           information.";
        reference
          "IEEE Std 1003.1-2008 - utsname.version";
      }

      leaf machine {
        type string;
        description
          "A vendor-specific identifier string representing
           the hardware in use.";
        reference
          "IEEE Std 1003.1-2008 - utsname.machine";
      }

    }

    container clock {
      description
        "Configuration and monitoring of the system
         date and time properties.";

      leaf current-datetime {
        type yang:date-and-time;
        config false;
        description
          "The current system date and time.";
      }

      leaf boot-datetime {
        type yang:date-and-time;
        config false;
        description
          "The system date and time when the NETCONF
           server last restarted.";
      }

      choice timezone {
        description
          "The system timezone information.";

        leaf timezone-location {
          if-feature timezone-location;
          type ianatz:iana-timezone;
          description
            "The TZ database location identifier string
             to use for the system, such as 'Europe/Stockholm'.";
        }

        leaf timezone-utc-offset {
          type int16 {
            range "-1500 .. 1500";
          }
          units "minutes";
          description
            "The number of minutes to add to UTC time to
             identify the timezone for this system.
             For example, 'UTC - 8:00 hours' would be
             represented as '-480'.  Note that automatic
             daylight savings time adjustment is not provided,
             if this object is used.";
        }
      }
    }

    container ntp {
      if-feature ntp;

      description
        "Configuration of the NTP client.";

      leaf enabled {
        type boolean;
        default true;
        description
          "Indicates that the system should attempt
           to synchronize the system clock with an
           NTP server from the 'ntp/server' list.";
      }

      list server {
        key address;
        description
          "List of NTP servers to use for
           system clock synchronization.  If '/system/ntp/enabled'
           is 'true', then the system will attempt to
           contact and utilize the specified NTP servers.";

        leaf association-type {
          type enumeration {
            enum server {
              description
                "Use client association mode.  This device
                 will not provide synchronization to the
                 configured NTP server.";
            }
            enum peer {
              description
                "Use symmetric active association mode.
                 This device may provide synchronization
                 to the configured NTP server.";
            }
            enum pool {
              description
                "Use client association mode with one or
                 more of the NTP servers found by DNS
                 resolution of the domain name given by
                 the 'address' leaf.  This device will not
                 provide synchronization to the servers.";
            }
          }
          default server;
          description
            "The desired association type for this NTP server.";
        }
        leaf address {
          type inet:host;
          description
            "The IP address or domain name of the NTP server.";
        }
        leaf enabled {
          type boolean;
          default true;
          description
            "Indicates whether this server is enabled for use or
             not.";
        }
        leaf iburst {
          type boolean;
          default false;
          description
            "Indicates whether this server should enable burst
             synchronization or not.";
        }
        leaf prefer {
          type boolean;
          default false;
          description
            "Indicates whether this server should be preferred
             or not.";
        }
      }
    }

    container dns {
      description
        "Configuration of the DNS resolver.";

      leaf-list search {
        type inet:domain-name;
        ordered-by user;
        description
          "An ordered list of domains to search when resolving
           a host name.";
      }
      leaf-list server {
        type inet:ip-address;
        ordered-by user;
        description
          "Addresses of the name servers that the resolver should
           query.

           Implementations MAY limit the number of entries in this
           leaf list.";
      }
      container options {
        description
          "Resolver options.  The set of available options has been
           limited to those that are generally available across
           different resolver implementations, and generally
           useful.";
        leaf timeout {
          type uint8 {
            range "1..max";
          }
          units "seconds";
          default "5";
          description
            "The amount of time the resolver will wait for a
             response from a remote name server before
             retrying the query via a different name server.";
        }
        leaf attempts {
          type uint8 {
            range "1..max";
          }
          default "2";
          description
            "The number of times the resolver will send a query to
             its name servers before giving up and returning an
             error to the calling application.";
        }
      }
    }

    container radius {
      if-feature radius;

      description
        "Configuration of the RADIUS client.";

      list server {
        key address;
        ordered-by user;
        description
          "List of RADIUS servers used by the device.";

        leaf address {
          type inet:host;
          description
            "The address of the RADIUS server.";
        }
        choice transport {
          mandatory true;
          description
            "The transport protocol specific parameters
             for this server.  It is expected that new
             case statements will be added over time to
             support other transport protocols.";
          case udp {
            container udp {
              description
                "Contains UDP specific configuration parameters
                 for RADIUS.";
              leaf authentication-port {
                type inet:port-number;
                default "1812";
                description
                  "The port number of the RADIUS server.";
              }
              leaf shared-secret {
                type string;
                mandatory true;
                nacm:default-deny-all;
                description
                  "The shared secret which is known to both the
                   RADIUS client and server.";
                reference
                  "RFC 2865: Remote Authentication Dial In User
                   Service";
              }
            }
          }
        }
        leaf authentication-type {
          type identityref {
            base radius-authentication-type;
          }
          default radius-pap;
          description
            "The authentication type requested from the RADIUS
             server.";
        }
      }
      container options {
        description
          "RADIUS client options.";

        leaf timeout {
          type uint8 {
            range "1..max";
          }
          units "seconds";
          default "5";
          description
            "The number of seconds the device will wait for a
             response from a RADIUS server before trying with a
             different server.";
        }
        leaf attempts {
          type uint8 {
            range "1..max";
          }
          default "2";
          description
            "The number of times the device will send a query to
             the RADIUS servers before giving up.";
        }
      }
    }

    container authentication {
      nacm:default-deny-write;
      if-feature authentication;

       description
         "The authentication configuration subtree.";

       leaf-list user-authentication-order {
         type identityref {
           base authentication-method;
         }
         must '(. != "sys:radius" or ../../radius/server)' {
           error-message
             "When 'radius' is used, a RADIUS server"
           + " must be configured.";
           description
             "When 'radius' is used as an authentication method,
              a RADIUS server must be configured.";
         }
         ordered-by user;

         description
           "When the device authenticates a user with
            a password, it tries the authentication methods in this
            leaf-list in order.  If authentication with one method
            fails, the next method is used.  If no method succeeds,
            the user is denied access.

            If the 'radius-authentication' feature is advertised by
            the NETCONF server, the 'radius' identity can be added to
            this list.

            If the 'local-users' feature is advertised by the
            NETCONF server, the 'local-users' identity can be
            added to this list.";
       }

       list user {
         if-feature local-users;
         key name;
         description
           "The list of local users configured on this device.";

         leaf name {
           type string;
           description
            "The user name string identifying this entry.";
         }
         leaf password {
           type crypt-hash;
           description
             "The password for this entry.";
         }
         list ssh-key {
           key name;
           description
             "A list of public SSH keys for this user.";
           reference
             "RFC 4253: The Secure Shell (SSH) Transport Layer
                        Protocol";

           leaf name {
             type string;
             description
               "An arbitrary name for the ssh key.";
           }
           leaf algorithm {
             type string;
             description
               "The public key algorithm name for this ssh key.

                Valid values are the values in the IANA Secure Shell
                (SSH) Protocol Parameters registry, Public Key
                Algorithm Names";
             reference
               "IANA Secure Shell (SSH) Protocol Parameters registry,
                Public Key Algorithm Names";
           }
           leaf key-data {
             type binary;
             description
               "The binary key data for this ssh key.";
           }
         }
       }
     }
  }

  rpc set-current-datetime {
    nacm:default-deny-all;
    description
      "Set the /system/clock/current-datetime leaf
       to the specified value.

       If the system is using NTP (i.e., /system/ntp/enabled
       is set to 'true'), then this operation will
       fail with error-tag 'operation-failed',
       and error-app-tag value of 'ntp-active'";
    input {
      leaf current-datetime {
        type yang:date-and-time;
        mandatory true;
        description
          "The current system date and time.";
      }
    }
  }

  rpc system-restart {
    nacm:default-deny-all;
    description
      "Request that the entire system be restarted immediately.
       A server SHOULD send an rpc reply to the client before
       restarting the system.";
  }

  rpc system-shutdown {
    nacm:default-deny-all;
    description
      "Request that the entire system be shut down immediately.
       A server SHOULD send an rpc reply to the client before
       shutting down the system.";
  }

}
	    

<CODE ENDS>

5. IANA Considerations

This document registers one URI in the IETF XML registry [RFC3688]. Following the format in RFC 3688, the following registration is requested to be made.

     URI: urn:ietf:params:xml:ns:yang:ietf-system
     Registrant Contact: The NETMOD WG of the IETF.
     XML: N/A, the requested URI is an XML namespace.
	    

This document registers one YANG module in the YANG Module Names registry [RFC6020].

  name:         ietf-system
  namespace:    urn:ietf:params:xml:ns:yang:ietf-system
  prefix:       sys
  reference:    RFC XXXX
	    

6. Security Considerations

The YANG module defined in this memo is designed to be accessed via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer and the mandatory-to-implement secure transport is SSH [RFC6242].

There are a number of data nodes defined in this YANG module which are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:

Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:

Some of the RPC operations in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations. These are the operations and their sensitivity/vulnerability:

7. Change Log

    -- RFC Ed.: remove this section before publication.  
	    

7.1. 00-01

7.2. 01-02

7.3. 02-03

7.4. 03-04

7.5. 04-05

7.6. 05-06

8. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004.
[RFC4252] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Authentication Protocol", RFC 4252, January 2006.
[RFC4253] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, January 2006.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, June 2011.
[RFC6557] Lear, E. and P. Eggert, "Procedures for Maintaining the Time Zone Database", BCP 175, RFC 6557, February 2012.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.
[RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, April 1992.
[RFC2865] Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000.
[RFC3418] Presuhn, R., "Management Information Base (MIB) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3418, December 2002.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In User Service (RADIUS) Authorization for Network Access Server (NAS) Management", RFC 5607, July 2009.
[FIPS.180-3.2008] National Institute of Standards and Technology, "Secure Hash Standard", FIPS PUB 180-3, October 2008.
[IEEE-1003.1-2008] Institute of Electrical and Electronics Engineers, "POSIX.1-2008", IEEE Standard 1003.1, March 2008.
[I-D.ietf-netmod-iana-timezones] Lange, J., "IANA Timezone Database YANG Module", Internet-Draft draft-ietf-netmod-iana-timezones-00, July 2012.
[I-D.ietf-netmod-rfc6021-bis] Schoenwaelder, J., "Common YANG Data Types", Internet-Draft draft-ietf-netmod-rfc6021-bis-01, March 2013.

Authors' Addresses

Andy Bierman YumaWorks EMail: andy@yumaworks.com
Martin Bjorklund Tail-f Systems EMail: mbj@tail-f.com