[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-bierman-netmod-system-mgmt) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 RFC 7317

Network Working Group                                         A. Bierman
Internet-Draft                                                 YumaWorks
Intended status: Standards Track                            M. Bjorklund
Expires: October 23, 2013                                 Tail-f Systems
                                                          April 21, 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 23, 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.





Bierman & Bjorklund     Expires October 23, 2013                [Page 1]


Internet-Draft           YANG System Management               April 2013


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
       1.1.1.  Terms  . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.2.  Tree Diagrams  . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Objectives . . . . . . . . . . . . . . . . . . . . . . . . . .  5
     2.1.  System Identification  . . . . . . . . . . . . . . . . . .  5
     2.2.  System Time Management . . . . . . . . . . . . . . . . . .  5
     2.3.  User Authentication  . . . . . . . . . . . . . . . . . . .  5
   3.  System Data Model  . . . . . . . . . . . . . . . . . . . . . .  6
     3.1.  System Identification  . . . . . . . . . . . . . . . . . .  6
     3.2.  System Time Management . . . . . . . . . . . . . . . . . .  6
     3.3.  DNS Resolver Model . . . . . . . . . . . . . . . . . . . .  6
     3.4.  RADIUS Client Model  . . . . . . . . . . . . . . . . . . .  7
     3.5.  User Authentication Model  . . . . . . . . . . . . . . . .  7
       3.5.1.  SSH Public Key Authentication  . . . . . . . . . . . .  8
       3.5.2.  Local User Password Authentication . . . . . . . . . .  8
       3.5.3.  RADIUS Password Authentication . . . . . . . . . . . .  9
     3.6.  System Control . . . . . . . . . . . . . . . . . . . . . .  9
   4.  System YANG module . . . . . . . . . . . . . . . . . . . . . . 10
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 26
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 27
   7.  Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.1.  00-01  . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.2.  01-02  . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.3.  02-03  . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.4.  03-04  . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.5.  04-05  . . . . . . . . . . . . . . . . . . . . . . . . . . 29
     7.6.  05-06  . . . . . . . . . . . . . . . . . . . . . . . . . . 30
   8.  Normative References . . . . . . . . . . . . . . . . . . . . . 31
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 33



















Bierman & Bjorklund     Expires October 23, 2013                [Page 2]


Internet-Draft           YANG System Management               April 2013


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:

   o  system administrative data configuration

   o  system identification monitoring

   o  system time-of-day configuration and monitoring

   o  user authentication configuration

   o  local users configuration

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:

   o  system: This term refers to the embodiment of the entire set of
      management interfaces that a single NETCONF server is supporting
      at a given moment.  The set of physical entities managed by a
      single NETCONF server can be static or it can change dynamically.

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:

   o  Brackets "[" and "]" enclose list keys.





Bierman & Bjorklund     Expires October 23, 2013                [Page 3]


Internet-Draft           YANG System Management               April 2013


   o  Abbreviations before data node names: "rw" means configuration
      (read-write) and "ro" state data (read-only).

   o  Symbols after data node names: "?" means an optional node and "*"
      denotes a "leaf-list".

   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.








































Bierman & Bjorklund     Expires October 23, 2013                [Page 4]


Internet-Draft           YANG System Management               April 2013


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.












Bierman & Bjorklund     Expires October 23, 2013                [Page 5]


Internet-Draft           YANG System Management               April 2013


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:








Bierman & Bjorklund     Expires October 23, 2013                [Page 6]


Internet-Draft           YANG System Management               April 2013


      +--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:

   o  publickey for local users over SSH

   o  password for local users over any transport

   o  password for RADIUS users over any transport

   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



Bierman & Bjorklund     Expires October 23, 2013                [Page 7]


Internet-Draft           YANG System Management               April 2013


   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.





Bierman & Bjorklund     Expires October 23, 2013                [Page 8]


Internet-Draft           YANG System Management               April 2013


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.

































Bierman & Bjorklund     Expires October 23, 2013                [Page 9]


Internet-Draft           YANG System Management               April 2013


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>



Bierman & Bjorklund     Expires October 23, 2013               [Page 10]


Internet-Draft           YANG System Management               April 2013


        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}';
       }



Bierman & Bjorklund     Expires October 23, 2013               [Page 11]


Internet-Draft           YANG System Management               April 2013


       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



Bierman & Bjorklund     Expires October 23, 2013               [Page 12]


Internet-Draft           YANG System Management               April 2013


      */

     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";



Bierman & Bjorklund     Expires October 23, 2013               [Page 13]


Internet-Draft           YANG System Management               April 2013


       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";
     }




Bierman & Bjorklund     Expires October 23, 2013               [Page 14]


Internet-Draft           YANG System Management               April 2013


     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";



Bierman & Bjorklund     Expires October 23, 2013               [Page 15]


Internet-Draft           YANG System Management               April 2013


       }

       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";
         }




Bierman & Bjorklund     Expires October 23, 2013               [Page 16]


Internet-Draft           YANG System Management               April 2013


         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;



Bierman & Bjorklund     Expires October 23, 2013               [Page 17]


Internet-Draft           YANG System Management               April 2013


             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 {



Bierman & Bjorklund     Expires October 23, 2013               [Page 18]


Internet-Draft           YANG System Management               April 2013


                 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



Bierman & Bjorklund     Expires October 23, 2013               [Page 19]


Internet-Draft           YANG System Management               April 2013


                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";



Bierman & Bjorklund     Expires October 23, 2013               [Page 20]


Internet-Draft           YANG System Management               April 2013


             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



Bierman & Bjorklund     Expires October 23, 2013               [Page 21]


Internet-Draft           YANG System Management               April 2013


                     "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;



Bierman & Bjorklund     Expires October 23, 2013               [Page 22]


Internet-Draft           YANG System Management               April 2013


         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;



Bierman & Bjorklund     Expires October 23, 2013               [Page 23]


Internet-Draft           YANG System Management               April 2013


              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'";



Bierman & Bjorklund     Expires October 23, 2013               [Page 24]


Internet-Draft           YANG System Management               April 2013


       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>






















Bierman & Bjorklund     Expires October 23, 2013               [Page 25]


Internet-Draft           YANG System Management               April 2013


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


































Bierman & Bjorklund     Expires October 23, 2013               [Page 26]


Internet-Draft           YANG System Management               April 2013


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:

   o  /system/clock/timezone: This choice contains the objects used to
      control the timezone used by the device.

   o  /system/ntp: This container contains the objects used to control
      the Network Time Protocol servers used by the device.

   o  /system/dns: This container contains the objects used to control
      the Domain Name System servers used by the device.

   o  /system/radius: This container contains the objects used to
      control the Remote Authentication Dial-In User Service servers
      used by the device.

   o  /system/authentication/user-authentication-order: This leaf
      controls how user login attempts are authenticated by the device.

   o  /system/authentication/user: This list contains the local users
      enabled on the system.

   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:

   o  /system/platform: This container has objects which may help
      identify the specific NETCONF server and/or operating system
      implementation used on the device.

   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:



Bierman & Bjorklund     Expires October 23, 2013               [Page 27]


Internet-Draft           YANG System Management               April 2013


   o  set-current-datetime: Changes the current date and time on the
      device.

   o  system-restart: Reboots the device.

   o  system-shutdown: Shuts down the device.













































Bierman & Bjorklund     Expires October 23, 2013               [Page 28]


Internet-Draft           YANG System Management               April 2013


7.  Change Log

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

7.1.  00-01

   o  added configuration-source identities

   o  added configuration-source leaf to ntp and dns (via grouping) to
      choose configuration source

   o  added association-type, iburst, prefer, and true leafs to the ntp-
      server list

   o  extended the ssh keys for a user to a list of keys. support all
      defined key algorithms, not just dsa and rsa

   o  clarified timezone-utc-offset description-stmt

   o  removed '/system/ntp/server/true' leaf from data model

7.2.  01-02

   o  added default-stmts to ntp-server/iburst and ntp-server/prefer
      leafs

   o  changed timezone-location leaf to use iana-timezone typedef
      instead of a string

7.3.  02-03

   o  removed configuration-source identities and leafs

7.4.  03-04

   o  removed ndots dns resolver option

   o  added radius-authentication-type identity, and identities for pap
      and chap, and a leaf to control which authentication type to use
      when communicating with the radius server

   o  made 0 an invalid value for timeouts and attempts

7.5.  04-05

   o  updated tree diagram explanation text





Bierman & Bjorklund     Expires October 23, 2013               [Page 29]


Internet-Draft           YANG System Management               April 2013


7.6.  05-06

   o  changed ntp/use-ntp to ntp/enabled

   o  changed ntp/ntp-server to ntp/server

   o  removed /system/platform/nodename leaf

   o  changed /system/name to /system/hostname

   o  simplified must expression in user-authentication-order

   o  added optional rounds to sha hash definition

   o  clarified the crypt-hash description

   o  clarified ntp descriptions

   o  clarified YANG module description to indicate that some system
      properties are supported, not the entire system

   o  clarified that system identification values are vendor specific,
      not the data node objects

   o  clarified sec. 2.2 and 2.3 to indicate that the server should also
      be capable of configuring these properties

   o  changed /system/dns/search from inet:host to inet:domain-name

   o  changed RFC6021 reference to 6021-bis

   o  changed /system/platform/nodename to /system/platform/hostname

   o  changed /system/radius/server/{leafs} to be within a choice and
      'udp' case statement so other transport specific parameters can
      augment this list or they can be added by the WG to a future
      version of this module. {leafs} are authentication-port and
      shared-secret.

   o  updated YANG tree diagrams for objects added in -05 and -06











Bierman & Bjorklund     Expires October 23, 2013               [Page 30]


Internet-Draft           YANG System Management               April 2013


8.  Normative References

   [FIPS.180-3.2008]
              National Institute of Standards and Technology, "Secure
              Hash Standard", FIPS PUB 180-3, October 2008, <http://
              csrc.nist.gov/publications/fips/fips180-3/
              fips180-3_final.pdf>.

   [I-D.ietf-netmod-iana-timezones]
              Lange, J., "IANA Timezone Database YANG Module",
              draft-ietf-netmod-iana-timezones-00 (work in progress),
              July 2012.

   [I-D.ietf-netmod-rfc6021-bis]
              Schoenwaelder, J., "Common YANG Data Types",
              draft-ietf-netmod-rfc6021-bis-01 (work in progress),
              March 2013.

   [IEEE-1003.1-2008]
              Institute of Electrical and Electronics Engineers,
              "POSIX.1-2008", IEEE Standard 1003.1, March 2008.

   [RFC1321]  Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
              April 1992.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [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.

   [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.

   [RFC5607]  Nelson, D. and G. Weber, "Remote Authentication Dial-In
              User Service (RADIUS) Authorization for Network Access
              Server (NAS) Management", RFC 5607, July 2009.



Bierman & Bjorklund     Expires October 23, 2013               [Page 31]


Internet-Draft           YANG System Management               April 2013


   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, June 2011.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              March 2012.

   [RFC6557]  Lear, E. and P. Eggert, "Procedures for Maintaining the
              Time Zone Database", BCP 175, RFC 6557, February 2012.


































Bierman & Bjorklund     Expires October 23, 2013               [Page 32]


Internet-Draft           YANG System Management               April 2013


Authors' Addresses

   Andy Bierman
   YumaWorks

   Email: andy@yumaworks.com


   Martin Bjorklund
   Tail-f Systems

   Email: mbj@tail-f.com







































Bierman & Bjorklund     Expires October 23, 2013               [Page 33]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/