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     Network Working Group                                       Barr Hibbs
     INTERNET-DRAFT                                        (no affiliation)
     Category:  Standards Track                                Glenn Waters
                                                            Nortel Networks
                                                              February 2004
     
     
          Dynamic Host Configuration Protocol for IPv4 (DHCPv4) Server MIB
     
     
                         <draft-ietf-dhc-server-mib-10.txt>
                     Saved Friday, February 06, 2004, 4:33:38 PM
     
     
     
     Status of this Memo
     
        This document is an Internet-Draft and is in full conformance with
        all provisions of Section 10 of RFC2026.
     
        Internet-Drafts are working documents of the Internet Engineering
        Task Force (IETF), its areas, and its working groups.  Note that
        other groups may also distribute working documents as Internet-
        Drafts.
     
        Internet-Drafts are draft documents valid for a maximum of six months
        and may be updated, replaced, or made obsolete 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."
     
        The list of current Internet-Drafts can be accessed at
        http://www.ietf.org/1id-abstracts.html.
     
        The list of Internet-Draft Shadow Directories can be accessed at
        http://www.ietf.org/shadow.html.
     
     Copyright Notice
     
        Copyright (C), 2003, The Internet Society.  All Rights Reserved.
     
     Abstract
     
        This memo defines an experimental portion of the Management
        Information Base (MIB) for use with network management protocols in
        the Internet Community.  In particular, it defines objects used for
        the management of Dynamic Host Configuration Protocol for IPv4
        (DHCPv4) and Bootstrap Protocol (BOOTP) servers.
     
     
     
     
     
     
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     Table of Contents
     
        1. Introduction...................................................2
        2. The Internet-Standard Management Framework.....................3
        3. Overview.......................................................3
          3.1. Relationship to Other MIBs.................................4
            3.1.1. DHCP MIB Extensions....................................4
            3.1.2. Host System MIB Extensions.............................4
            3.1.3. DHCP Client MIB Extensions.............................4
            3.1.4. DHCP Relay Agent MIB Extensions........................5
            3.1.5. DHCPv6 MIB Extensions..................................5
          3.2. Textual Conventions Introduced in this MIB.................5
            3.2.1. Dhcpv4PhysicalAddress..................................5
          3.3. BOOTP and DHCP Counter Groups..............................5
            3.3.1. Discontinuities........................................6
            3.3.2. Counter Rollover.......................................7
          3.4. Server Configuration Group.................................7
        4. Definitions....................................................9
        5. Intellectual Property.........................................33
        6. Acknowledgements..............................................33
        7. IANA Considerations...........................................33
        8. Security Considerations.......................................34
        9. References....................................................35
          9.1. Normative References......................................35
          9.2. Informative References....................................35
        10. Editors' Addresses...........................................36
        11. Full Copyright Statement.....................................36
     
     
     
     1. Introduction
     
        This memo is a product of the DHCP Working Group and defines a
        portion of the Management Information Base (MIB) for use with
        network management protocols in the Internet community.  In
        particular, it describes a set of extensions that DHCPv4 and
        Bootstrap Protocol (BOOTP) servers implement.  Many implementations
        support both DHCPv4 and BOOTP within a single server and hence this
        memo describes the MIB for both DHCPv4 and BOOTP servers.
     
        This memo does not cover DHCPv4/BOOTP client nor relay agent MIB
        extensions:  these are possibly the subjects of future investigation
        [see discussion in section 3.1.]  Also excluded from this MIB
        extension in the interest of simplicity are DHCP Dynamic DNS
        Updating, Failover, Authentication, and Load Balancing:  these
        functions and features could be subjects of future MIB extensions.
        Provision is also made for Standards-Track additions to the DHCP
        Message Type (option 61.)
     
     
     
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        This memo is based on the Internet-standard Network Management
        Framework as defined by documents [RFC2578, RFC2579, RFC2580].
     
        Objects defined in this MIB allow access to and control of DHCP
        Server Software.  Servers MAY also provide additional management
        capabilities using the Applications MIB [RFC2287].
     
        The key words "MUST," "MUST NOT," "REQUIRED," "SHALL," "SHALL NOT,"
        "SHOULD," "SHOULD NOT," "RECOMMENDED,"  "MAY," and "OPTIONAL" in
        this document are to be interpreted as described in [RFC2119].
     
     
     2. The Internet-Standard Management Framework
     
        For a detailed overview of the documents that describe the current
        Internet-Standard Management Framework, please refer to section 7 of
        RFC 3410 [RFC3410], Managed objects are accessed via a virtual
        information store, termed the Management Information Base or MIB.
        MIB objects are generally accessed through the Simple Network
        Management Protocol (SNMP).  Objects in the MIB are defined using
        the mechanisms defined in the Structure of Management Information
        (SMI).  This memo specifies a MIB module that is compliant to the
        SMIv2, which is described in STD 58, [RFC2578], STD 58, [RFC2579]
        and STD 58, [RFC2580].
     
     
     3. Overview
     
        In the tradition of the Simple Network Management Protocol (SNMP),
        the minimum number of objects possible is defined in this MIB, while
        still providing as rich a set of management information as possible.
        An object is left out of this MIB when it can be derived from other
        objects that are provided.  Further to the tradition of the SNMP,
        computationally intense operations are left to the domain of the
        management station.  Thus, this MIB provides a set of objects from
        which other management information can be derived.
     
        Provision for future extensions to cover DHCPv4 clients and relay
        agents, and DHCPv6 extensions are implied by the top-level structure
        illustrated in section 3.1.1.
     
        The examples provided in sections 3.3 through 3.5 are not meant to
        be comprehensive but are illustrative of the potential uses of the
        objects defined by this MIB.
     
     
     
     
     
     
     
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     3.1. Relationship to Other MIBs
     
     
     3.1.1. DHCP MIB Extensions
     
        The DHCP MIB extensions will be the "dhcp" branch of the standard
        MIB-2 tree, as illustrated by the following diagram:
     
          +-------+
          | MIB-2 |
          +---+---+
              |
              |
          +---+---+
          |  dhcp |
          +---+---+
              |
              |
              +--------------+---------------+----------------+
              |              |               |                |
        +-----+-----+  +-----+----+  +-------+-------+  +-----+-----+
        |  dhcp-v4  |  |  dhcp-v4 |  |    dhcp-v4    |  |dhcp-v6 MIB|
        |Server MIB |  |Client MIB|  |Relay Agent MIB|  |Extensions |
        |(this memo)|  | (future) |  | (future work) |  | (future)  |
        +-----------+  +----------+  +---------------+  +-----------+
     
     
        The DHCP MIBs share a common branching point but will be
        independently defined by individual memos.
     
     
     3.1.2. Host System MIB Extensions
     
        The Host System MIB [RFC1123] provides for information, command, and
        control of the host computer system on which a DHCP server resides.
        The DHCP Server MIB specifically does not include any objects that
        may be accessible using the Host System MIB.
     
     
     3.1.3. DHCP Client MIB Extensions
     
        Development of this set of MIB extensions is a natural path given
        the increasing interest in desktop and client system management.  It
        will share a common branch point in the MIB tree with the other DHCP
        MIB Extensions, and may use many of the same textual conventions.
     
     
     
     
     
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     3.1.4. DHCP Relay Agent MIB Extensions
     
        If this set of MIB extensions is ever developed, it will share a
        common branch point in the MIB tree with the other DHCP MIB
        Extensions, and will use many of the same textual conventions.
     
     
     3.1.5. DHCPv6 MIB Extensions
     
        If this set of MIB extensions is ever developed, it will share a
        common branch point in the MIB tree with the other DHCP MIB
        Extensions, and will likely use very different textual conventions
        as the protocol differs significantly from DHCPv4.
     
     
     3.2. Textual Conventions Introduced in this MIB
     
        One conceptual data type has been introduced in this document.  No
        changes to the SMI or SNMP are necessary to support this convention.
     
     
     3.2.1. Dhcpv4PhysicalAddress
     
        This data type contains the type of hardware address represented by
        MacAddress, as defined for ARP messages, the length in octets of
        MacAddress, and the actual layer 1 hardware address.
     
     
     3.3. BOOTP and DHCP Counter Groups
     
        This section describes some of the management information that can
        be derived from the objects provided in the counter groups.
     
        In this context, a "valid" packet is one which has an identifiable
        message type and has passed all format and validation checks that
        the DHCP server implements.  Not all servers validate received
        packets in the same way, so there will be differences in the counts
        reported by different servers.  It is appropriate to simply accept
        the server's notion of what constitutes a valid packet.
     
        The total number of valid DHCP packets received by the server is
        computed as:
     
           (dhcpv4CountDiscovers + dhcpv4CountRequests +
           dhcpv4CountReleases + dhcpv4CountDeclines + dhcpv4CountInforms
           + dhcpv4CountLeaseQueries)
     
        The total number of valid packets (BOOTP and DHCP) received is
        computed as:
     
     
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           (total number of valid DHCP packets) + bootpCountRequests)
     
        The total number of packets received is computed as:
     
          (total number of valid packets) + bootpCountInvalids +
          dhcpv4CountInvalids
     
        Similar to the received computations, the total number of DHCP
        packets sent by the server is computed as:
     
           dhcpv4CountOffers + dhcpv4CountAcks + dhcpv4CountNaks
     
        The number of packets (BOOTP and DHCP) sent by the server is
        computed as:
     
           (total number of DHCP packets sent) + (bootpCountReplies)
     
     
     3.3.1.  Discontinuities
     
        Hosts for DHCP servers, and the DHCP servers themselves, are
        generally quite reliable but occasionally counter values may be
        discontinuous between successive GETs.  There are several cases of
        interest:
     
          o Server fails and is restarted, resetting all counters to zero.
     
          o Server fails and is restarted, with counters in an unknown
            state.
     
          o Server fails and is restarted, with counters restored to some
            previously checkpointed value.
     
        The first case MAY occur when a server and agent are incapable of
        restarting to a "last known good" state, and a manager MUST be
        capable of recognizing this case.  There is little a manager can do
        other than recognize a reset to zero has occurred and continue from
        the point of restart.
     
        The second case is currently the Best Current Practice for SNMP
        managers.  Because of the uncertain state of counters following a
        server restart, a manager MUST discard data from the outage interval
        and restart its calculations.
     
        The third case SHOULD arise only if agents take periodic snapshots
        at different intervals than responding to a GET request.  While the
        counts reported in the first GET response following the outage were
        accurate at some time, they MAY NOT be completely current.  If this
        occurs, the manager MAY have to accept that data has been lost,
        perhaps discarding accumulated data, and continue.
     
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     3.3.2. Counter Rollover
     
        Counter objects increment at different rates.  It can be expected
        that some counter will reach its maximum value and rollover to zero
        while others are nowhere near their maximum value.  When a counter's
        value at time t2 is less than its value at time t1, the manager
        SHOULD initially assume that a discontinuity has occurred and
        perform appropriate data validation to determine if the value has
        rolled over.  If a single rollover has occurred, the value used in
        calculation SHOULD be:
     
           [(maximum value of counter) - (value at time t1)] + (value at
           time t2) + 1
     
        Managers SHOULD be alert to the possibility of a counter rolling
        over more than once during the sampling interval.  If this is
        likely to occur (due to very short leases, very large numbers of
        clients, network topology, and the presence of unreliable clients
        or intermediate network equipment) a manager SHOULD carefully
        examine each detected counter rollover to determine if the data
        can be used or should be discarded.
     
     
     3.4. Server Configuration Group
     
        The server configuration group contains objects that describe the
        client host configuration information that is held in the server to
        be offered to requesting clients.  Some of the configuration
        information is static (e.g., a statically configured IPv4 address)
        and some of the configuration is dynamic (e.g., an assigned DHCP
        lease).  The intent of the server configuration group is to be able
        to read the server's configuration.
     
        The configuration information defines a minimal set of information
        that most servers should be able to provide.  Each row of the
        dhcpv4ServerSubnetTable lists the subnet address, the subnet mask,
        and the shared network name that is equivalent to the subnet.
        Equivalence is defined as more than one subnet being present on the
        same network segment as some other subnet.
     
        The dhcpv4ServerRangeTable lists the start and end IPv4 addresses of
        the ranges and the subnet of which the range is a member.  The
        dhcpv4ServerRangeInUse object indicates the amount of the range that
        is currently in use, either through dynamic allocation or being
        reserved.  The range size can be computed as:
     
           dhcpv4ServerRangeStartAddress - dhcpv4ServerRangeEndAddress +
           1
     
     
     
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        The dhcpv4ServerClientTable provides information about the static
        and dynamic addresses that the server contains in its configuration.
        Addresses can be:
     
          o Static, in which case they are predefined though the server's
            configuration.  Static addresses may or may not have been
            previously served by the server;
     
          o Dynamic, in which case the server has served the addresses and
            it is currently in active use by a host;
     
          o Expired, in which case the server had previously assigned the
            address, but the lease time has expired and is retained by the
            server for possible future use by the same client;
     
          o Configuration-reserved, in which case the address is not
            available for the server to allocate to a client.  A
            configuration-reserved address is one that has been reserved by
            the administrator.  An example of a configuration-reserved
            address is an address that is assigned to a client, not through
            DHCP (e.g., statically assigned), and the address is within a
            DHCP range; and
     
          o Server-reserved, in which case the server has taken the address
            out of use.  Examples of server-reserved addresses are those
            that have been declined (i.e., through a DHCPDECLINE) by a
            client or those that have responded to an ICMP echo before they
            were assigned.
     
        The protocol used to allocate the address can be determined from the
        "dhcpv4ServerClientServedProtocol" object.  This object indicates
        whether the address has never been served, or whether BOOTP or DHCP
        was used to allocate the address.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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     4. Definitions
     
     
        DHCP-SERVER-MIB DEFINITIONS ::= BEGIN
     
        IMPORTS
           Counter64, Gauge32, Unsigned32, MODULE-IDENTITY, OBJECT-TYPE,
           OBJECT-IDENTITY, NOTIFICATION-TYPE, mib-2
              FROM SNMPv2-SMI
     
           TEXTUAL-CONVENTION, DateAndTime FROM SNMPv2-TC
     
           SnmpAdminString FROM SNMP-FRAMEWORK-MIB
     
           InetAddressIPv4, InetAddressPrefixLength
           FROM INET-ADDRESS-MIB
     
           MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
           FROM SNMPv2-CONF;
     
     
        dhcp  MODULE-IDENTITY
           LAST-UPDATED   "200402061633Z"
           ORGANIZATION
              "IETF DHC Working Group
              General Discussion: dhcwg@ietf.org
              Subscribe: http://www1.ietf.org/mailman/listinfo/dhcwg
              Archive: http://www1.ietf.org/mailman/listinfo/dhcwg
              Chair: Ralph Droms, rdroms@cisco.com"
           CONTACT-INFO
              "         Richard Barr Hibbs
              Postal:  952 Sanchez Street
                       San Francisco, California 94114-3362
                       USA
                 Tel:  +1-(415)-648-3920
                 Fax:  +1-(415)-648-9017
              E-mail:  rbhibbs@pacbell.net
     
                       Glenn Waters
              Postal:  Nortel Networks, Inc.
                       310-875 Carling Avenue
                       Ottawa, Ontario K1S 5P1
                       Canada
                 Tel:  +1-(613)-798-4925
              E-mail:  gww@NortelNetworks.com"
           DESCRIPTION
              "The MIB module for entities implementing the server side of
              the Bootstrap Protocol (BOOTP) and the Dynamic Host
              Configuration protocol (DHCP) for Internet Protocol version
     
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              4(IPv4).  This MIB does not include support for Dynamic DNS
              (DDNS) updating nor for the DHCP Failover Protocol.
     
              Copyright (C) The Internet Society (2003).  This version of
              this MIB module is part of RFC xxxx;  see the RFC itself for
              full legal notices."
              -- RFC Editor assigns xxxx and removes this comment
     
           REVISION "200402061633Z" -- 6 February 2004
           DESCRIPTION "Initial Version, published as RFC xxxx."
              -- RFC Editor assigns xxxx and removes this comment
           ::= { mib-2 9999 } -- IANA will make official assignment
     
     
        -- Textual conventions defined by this memo
     
        Dhcpv4PhysicalAddress ::= TEXTUAL-CONVENTION
           DISPLAY-HINT   "1d,1d,1x:1x:1x:1x:1x:1x"
           STATUS         current
           DESCRIPTION
              "A DHCP-specific encoding of the physical address type and
              physical address, intended to mirror the representation of
              physical addresses in DHCP messages.  The first octet of this
              object contains the hardware type from the 'htype' field of
              the DHCP message, the second octet of this object contains the
              hardware length from the 'hlen' field, and the remaining
              octets contain the hardware address from the 'chaddr' field."
           REFERENCE      "RFC 2131"
           SYNTAX         OCTET STRING (SIZE(18))
     
     
        -- declare top-level MIB objects
     
        dhcpv4Server  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "DHCPv4 Server MIB objects are defined in this branch."
           ::= { dhcp 1 }
     
        dhcpv4ServerObjects  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "DHCP Server MIB server identification objects are all defined
              in this branch."
        ::= { dhcpv4Server 1 }
     
        dhcpv4ServerSystem  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Group of objects that are related to the overall system."
     
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        ::= { dhcpv4ServerObjects 1 }
     
        bootpCounters  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Group of objects that count various BOOTP events."
        ::= { dhcpv4ServerObjects 2 }
     
        dhcpv4Counters  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Group of objects that count various DHCPv4 events."
        ::= { dhcpv4ServerObjects 3 }
     
        dhcpv4ServerConfiguration  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Objects that contain pre-configured and dynamic configuration
              information."
        ::= { dhcpv4ServerObjects 6 }
     
        dhcpv4ServerNotifyObjects  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Objects that are used only in notifications."
           ::= { dhcpv4ServerObjects 7 }
     
     
        -- dhcpv4ServerSystemObjects Group
     
        dhcpv4ServerSystemDescr  OBJECT-TYPE
           SYNTAX      SnmpAdminString (SIZE(0..255))
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "A textual description of the server.  This value SHOULD
              include the full name and version identification of the
              server."
           ::= { dhcpv4ServerSystem 1 }
     
        dhcpv4ServerSystemObjectID  OBJECT-TYPE
           SYNTAX      OBJECT IDENTIFIER
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The vendor's authoritative identification of the network
              management subsystem contained in this entity.  This value is
              allocated within the SMI enterprise subtree (1.3.6.1.4.1) and
              provides an easy and unambiguous means for determining what
              kind of server is being managed.  For example, if vendor Ohso
     
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              Soft, Inc. is assigned the subtree 1.3.6.1.4.1.4242, it might
              assign the identifier 1.3.6.1.4.1.4242.1.1 to its Ursa DHCP
              Server."
           ::= { dhcpv4ServerSystem 2 }
     
     
        -- bootpCounterObjects Group
     
        bootpCountRequests  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of packets received that contain a Message Type of
              1 (BOOTREQUEST) in the first octet and do not contain option
              number 53 (DHCP Message Type) in the options."
           REFERENCE
              "RFC-2131."
           ::= { bootpCounters 1 }
     
        bootpCountInvalids  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of packets received that do not contain a Message
              Type of 1 (BOOTREQUEST) in the first octet or are not valid
              BOOTP packets (e.g., too short, invalid field in packet
              header)."
           ::= { bootpCounters 2 }
     
        bootpCountReplies  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of packets sent that contain a Message Type of 2
              (BOOTREPLY) in the first octet and do not contain option
              number 53 (DHCP Message Type) in the options."
           REFERENCE
              "RFC-2131."
           ::= { bootpCounters 3 }
     
        bootpCountDroppedUnknownClients  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
     
     
     
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              "The number of BOOTP packets dropped due to the server not
              recognizing or not providing service to the hardware address
              received in the incoming packet."
           ::= { bootpCounters 4 }
     
        bootpCountDroppedNotServingSubnet  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of BOOTP packets dropped due to the server not
              being configured or not otherwise able to serve addresses on
              the subnet from which this message was received."
           ::= { bootpCounters 5 }
     
     
        -- DHCP Counters Group
     
        dhcpv4CountDiscovers  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPDISCOVER (option 53 with value 1) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 1 }
     
        dhcpv4CountOffers  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPOFFER (option 53 with value 2) packets
              sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 2 }
     
        dhcpv4CountRequests  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPREQUEST (option 53 with value 3) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 3}
     
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        dhcpv4CountDeclines  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPDECLINE (option 53 with value 4) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 4 }
     
        dhcpv4CountAcks  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPACK (option 53 with value 5) packets sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
        ::= { dhcpv4Counters 5 }
     
        dhcpv4CountNaks  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPNACK (option 53 with value 6) packets
              sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 6 }
     
        dhcpv4CountReleases  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPRELEASE (option 53 with value 7) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 7 }
     
        dhcpv4CountInforms  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
     
     
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              "The number of DHCPINFORM (option 53 with value 8) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpv4Counters 8 }
     
        dhcpv4CountForcedRenews  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPFORCERENEW (option 53 with value 9) packets
              sent."
           REFERENCE
              " RFC 3203, DHCP reconfigure extension."
           ::= { dhcpv4Counters 9 }
     
        dhcpv4CountInvalids  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCP packets received whose DHCP message type
              (i.e., option number 53) is not understood or handled by the
              server."
           ::= { dhcpv4Counters 10 }
     
        dhcpv4CountDroppedUnknownClient  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCP packets dropped due to the server not
              recognizing or not providing service to the client-id and/or
              hardware address received in the incoming packet."
           ::= { dhcpv4Counters 11 }
     
        dhcpv4CountDroppedNotServingSubnet  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCP packets dropped due to the server not
              being configured or not otherwise able to serve addresses on
              the subnet from which this message was received."
           ::= { dhcpv4Counters 12 }
     
     
        -- DHCP Server Configuration
     
     
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        -- dhcpv4ServerSharedNetObjects Group
     
        dhcpv4ServerSharedNetTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF Dhcpv4ServerSharedNetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A list of shared networks that are configured in the server.
              A shared network is the logical aggregation of one or more
              subnets that share a common network segment (e.g., multi-
              tapped coaxial cable, wiring hub, or switch).  This table is
              present ONLY for those servers that organize the ranges of
              addresses available for assignment where a higher-level
              grouping (i.e., the 'shared' network) exists above ranges and
              subnets."
           ::= { dhcpv4ServerConfiguration 1 }
     
        dhcpv4ServerSharedNetEntry  OBJECT-TYPE
           SYNTAX      Dhcpv4ServerSharedNetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A logical row in the dhcpv4ServerSharedNetTable."
           INDEX {
              dhcpv4ServerSharedNetName
           }
           ::= { dhcpv4ServerSharedNetTable 1}
     
        Dhcpv4ServerSharedNetEntry ::= SEQUENCE {
           dhcpv4ServerSharedNetName                    SnmpAdminString,
           dhcpv4ServerSharedNetFreeAddrLowThreshold    Unsigned32,
           dhcpv4ServerSharedNetFreeAddrHighThreshold   Unsigned32,
           dhcpv4ServerSharedNetFreeAddresses           Unsigned32,
           dhcpv4ServerSharedNetReservedAddresses       Unsigned32,
           dhcpv4ServerSharedNetTotalAddresses          Unsigned32
        }
     
        dhcpv4ServerSharedNetName  OBJECT-TYPE
           SYNTAX      SnmpAdminString (SIZE(1..100))
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The name of the shared network, which uniquely identifies an
              entry in the dhcpv4ServerSharedNetTable."
           ::= { dhcpv4ServerSharedNetEntry 1 }
     
        dhcpv4ServerSharedNetFreeAddrLowThreshold  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
     
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           DESCRIPTION
              "The low threshold for available free addresses in this shared
              network.  If the value for available free addresses in this
              shared network becomes equal to or less than this value, a
              dhcpv4ServerFreeAddressLow event is generated for this shared
              network.  No more dhcpv4ServerFreeAddressLow events will be
              generated for this subnet during this execution of the DHCP
              server until the value for available free addresses has
              exceeded the value of
              dhcpv4ServerSharedNetFreeAddrHighThreshold."
           ::= { dhcpv4ServerSharedNetEntry 2 }
     
        dhcpv4ServerSharedNetFreeAddrHighThreshold  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The high threshold for available free addresses in this
              shared network.  If a dhcpv4ServerFreeAddressLow event was
              generated for this subnet, and the value for available free
              addresses has exceeded the value of
              dhcpv4ServerSubnetFreeAddrHighThreshold, then a
              dhcpv4ServerFreeAddressHigh event will be generated.  No more
              dhcpv4ServerFreeAddressHigh events will be generated for this
              subnet during this execution of the DHCP server until the
              value for available free addresses becomes equal to or less
              than the value of dhcpv4ServerSubnetFreeAddrLowThreshold."
           ::= { dhcpv4ServerSharedNetEntry 3 }
     
        dhcpv4ServerSharedNetFreeAddresses  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IPv4 addresses which are available within this
              shared network.  If the server does not count free addresses
              by shared network segment, this value will be zero."
           ::= { dhcpv4ServerSharedNetEntry 4 }
     
        dhcpv4ServerSharedNetReservedAddresses  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IPv4 addresses which are reserved (not
              available for assignment) within this shared network.  If the
              server does not count reserved addresses by shared network
              segment, this value will be zero."
           ::= { dhcpv4ServerSharedNetEntry 5 }
     
     
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        dhcpv4ServerSharedNetTotalAddresses  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IPv4 addresses which are available within this
              shared network.  If the server does not count total addresses
              by shared network segment, this value will be zero."
           ::= { dhcpv4ServerSharedNetEntry 6 }
     
     
        -- dhcpv4ServerSubnetObjects Group
     
        dhcpv4ServerSubnetTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF Dhcpv4ServerSubnetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A list of subnets that are configured in this server."
           ::= { dhcpv4ServerConfiguration 2 }
     
        dhcpv4ServerSubnetEntry  OBJECT-TYPE
           SYNTAX      Dhcpv4ServerSubnetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A logical row in the dhcpv4ServerSubnetTable."
           INDEX {
              dhcpv4ServerSubnetAddress
           }
           ::= { dhcpv4ServerSubnetTable 1 }
     
        Dhcpv4ServerSubnetEntry ::= SEQUENCE {
           dhcpv4ServerSubnetAddress                 InetAddressIPv4,
           dhcpv4ServerSubnetMask
              InetAddressPrefixLength,
           dhcpv4ServerSubnetSharedNetworkName       SnmpAdminString,
           dhcpv4ServerSubnetFreeAddrLowThreshold    Unsigned32,
           dhcpv4ServerSubnetFreeAddrHighThreshold   Unsigned32,
           dhcpv4ServerSubnetFreeAddresses           Unsigned32
        }
     
        dhcpv4ServerSubnetAddress  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The IPv4 address of the subnet entry in the
              dhcpv4ServerSubnetTable."
           ::= { dhcpv4ServerSubnetEntry 1 }
     
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        dhcpv4ServerSubnetMask  OBJECT-TYPE
           SYNTAX      InetAddressPrefixLength
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The subnet mask of the subnet.  This MUST be the same as the
              value of DHCP option 1 offered to clients on this subnet."
           ::= { dhcpv4ServerSubnetEntry 2 }
     
        dhcpv4ServerSubnetSharedNetworkName  OBJECT-TYPE
           SYNTAX      SnmpAdminString (SIZE(1..100))
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The shared subnet name (used as an index into the server
              shared subnet table) to which this subnet belongs.  This value
              will be null for servers that do not organize or describe
              networks in this manner."
           ::= { dhcpv4ServerSubnetEntry 3 }
     
        dhcpv4ServerSubnetFreeAddrLowThreshold  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The low threshold for available free addresses in this
              subnet.  If the value for available free addresses in this
              subnet becomes equal to or less than this value, a
              dhcpv4ServerSubnetFreeAddrLowThreshold event will be generated
              for this shared network.  No more
              dhcpv4ServerSubnetFreeAddrLowThreshold events will be
              generated for this subnet during this execution of the DHCP
              server until the value for available free addresses has
              exceeded the value of
              dhcpv4ServerSubnetFreeAddrHighThreshold."
           ::= { dhcpv4ServerSubnetEntry 4 }
     
        dhcpv4ServerSubnetFreeAddrHighThreshold  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The high threshold for available free addresses in this
              subnet.  If a dhcpv4ServerSubnetFreeAddrLowThreshold event has
              been generated for this subnet, and the value for available
              free addresses has exceeded the value of
              dhcpv4ServerSubnetFreeAddrHighThreshold, then a
              dhcpv4ServerFreeAddressHigh event will be generated.  No more
              dhcpv4ServerFreeAddressHigh events will be generated for this
     
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              subnet during this execution of the DHCP server until the
              value for available free addresses becomes equal to or less
              than the value of dhcpv4ServerSubnetFreeAddrLowThreshold."
           ::= { dhcpv4ServerSubnetEntry 5 }
     
        dhcpv4ServerSubnetFreeAddresses  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of free IPv4 addresses which are available in this
              subnet."
           ::= { dhcpv4ServerSubnetEntry 6 }
     
     
        -- dhcpv4ServerRangeObjects Group
     
        dhcpv4ServerRangeTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF Dhcpv4ServerRangeEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A list of ranges that are configured on this server."
           ::= { dhcpv4ServerConfiguration 3 }
     
        dhcpv4ServerRangeEntry  OBJECT-TYPE
           SYNTAX      Dhcpv4ServerRangeEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A logical row in the dhcpv4ServerRangeTable."
           INDEX {
              dhcpv4ServerRangeStartAddress,
              dhcpv4ServerRangeEndAddress
           }
           ::= { dhcpv4ServerRangeTable 1 }
     
        Dhcpv4ServerRangeEntry ::= SEQUENCE {
           dhcpv4ServerRangeStartAddress       InetAddressIPv4,
           dhcpv4ServerRangeEndAddress         InetAddressIPv4,
           dhcpv4ServerRangeSubnetMask         InetAddressPrefixLength,
           dhcpv4ServerRangeInUse              Gauge32,
           dhcpv4ServerRangeOutstandingOffers  Gauge32
        }
     
        dhcpv4ServerRangeStartAddress  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
     
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              "The IPv4 address of the first address in the range.  The
              value of dhcpv4ServerRangeStartAddress MUST be less than or
              equal to the value of dhcpv4ServerRangeEndAddress."
           ::= { dhcpv4ServerRangeEntry 1 }
     
        dhcpv4ServerRangeEndAddress  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The IPv4 address of the last address in the range.  The value
              of dhcpv4ServerRangeEndAddress MUST be greater than or equal
              to the value of dhcpv4ServerRangeStartAddress."
           ::= { dhcpv4ServerRangeEntry 2 }
     
        dhcpv4ServerRangeSubnetMask  OBJECT-TYPE
           SYNTAX      InetAddressPrefixLength
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The subnet address mask for this range."
           ::= { dhcpv4ServerRangeEntry 3 }
     
        dhcpv4ServerRangeInUse  OBJECT-TYPE
           SYNTAX      Gauge32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of addresses in this range that are currently in
              use.  This number includes those addresses whose lease has not
              expired and addresses which have been reserved (either by the
              server or through configuration)."
           ::= { dhcpv4ServerRangeEntry 4 }
     
        dhcpv4ServerRangeOutstandingOffers  OBJECT-TYPE
           SYNTAX      Gauge32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of outstanding DHCPOFFER messages for this range
              is reported with this value.  An offer is outstanding if the
              server has sent a DHCPOFFER message to a client, but has not
              yet received a DHCPREQUEST message from the client nor has the
              server-specific timeout (limiting the time in which a client
              can respond to the offer message) for the offer message
              expired."
           ::= { dhcpv4ServerRangeEntry 5 }
     
     
        -- dhcpv4ServerClientObjects Group
     
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        dhcpv4ServerClientTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF Dhcpv4ServerClientEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "An optional list of addresses that are known by this server.
              The list MUST contain addresses that have not expired.  The
              list MUST NOT contain addresses that have never been assigned
              by the server UNLESS the lease is pre-configured in the server
              (e.g., a static lease for a host).  Expired leases MAY appear
              during the time they are 'remembered' by the server for
              subsequent assignment to the same host."
           ::= { dhcpv4ServerConfiguration 4 }
     
        dhcpv4ServerClientEntry  OBJECT-TYPE
           SYNTAX      Dhcpv4ServerClientEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A logical row in the dhcpv4ServerClientTable."
           INDEX {
              dhcpv4ServerClient
           }
           ::= { dhcpv4ServerClientTable 1 }
     
        Dhcpv4ServerClientEntry ::= SEQUENCE {
           dhcpv4ServerClient                  InetAddressIPv4,
           dhcpv4ServerClientSubnetMask        InetAddressPrefixLength,
           dhcpv4ServerClientRange          InetAddressIPv4,
           dhcpv4ServerClientLeaseType         INTEGER,
           dhcpv4ServerClientTimeRemaining     Unsigned32,
           dhcpv4ServerClientAllowedProtocol   INTEGER,
           dhcpv4ServerClientServedProtocol INTEGER,
           dhcpv4ServerClientPhysicalAddress   Dhcpv4PhysicalAddress,
           dhcpv4ServerClientClientId       OCTET STRING,
           dhcpv4ServerClientHostName       SnmpAdminString,
           dhcpv4ServerClientDomainName        SnmpAdminString
        }
     
        dhcpv4ServerClient  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The IPv4 address of this entry in the
              dhcpv4ServerClientTable."
           ::= { dhcpv4ServerClientEntry 1 }
     
        dhcpv4ServerClientSubnetMask  OBJECT-TYPE
     
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           SYNTAX      InetAddressPrefixLength
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The subnet mask (DHCP option 1) provided to the client
              offered this address.  The subnet, resulting from logically
              ANDing the subnet mask with the entry's IPv4 address, MUST be
              configured on this server and appear as a row in the
              dhcpSubnetTable."
           ::= { dhcpv4ServerClientEntry 2 }
     
        dhcpv4ServerClientRange  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The starting IPv4 address (dhcpv4ServerRangeStartAddress
              object) of the range to which this address belongs.  If the
              address does not fall into one of the configured ranges (e.g.,
              a statically configured address on a subnet) the range MAY be
              0.0.0.0."
           ::= { dhcpv4ServerClientEntry 3 }
     
        dhcpv4ServerClientLeaseType  OBJECT-TYPE
           SYNTAX      INTEGER {
              static(1),
              dynamic(2),
              expired(3),
              configurationReserved(4),
              serverReserved(5)
           }
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The type of this address.  Types are:
                (1) Static addresses defined by the server configuration.
                (2) Dynamic addresses defined by the server configuration
                    AND actually assigned by the server.
                (3) Expired dynamic addresses, previously assigned by the
                    server, and 'remembered' for subsequent assignment to
                    the same host.
                (4) Addresses reserved (i.e., not assignable) by the server
                    configuration.
                (5) Addresses previously assigned by the server, but
                    temporarily or permanently removed from assignable state
                    for some reason, e.g., the server received an ICMP
                    ECHOREPLY for the IPv4 address or a DHCPDECLINE message
                    has been received for the IPv4 address."
           ::= { dhcpv4ServerClientEntry 4 }
     
     
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        dhcpv4ServerClientTimeRemaining  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of seconds until the lease expires.  A value of
              4294967295 (i.e., 0xFFFFFFFF) SHOULD be used for leases that
              have a lease time which is 'infinite' and for BOOTP leases."
           ::= { dhcpv4ServerClientEntry 5 }
     
        dhcpv4ServerClientAllowedProtocol  OBJECT-TYPE
           SYNTAX      INTEGER {
              none(1),
              bootp(2),
              dhcp(3),
              bootpOrDhcp(4)
           }
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The type of protocol that is allowed to be used to serve this
              address.  A type of none (1) indicates that the address is not
              available to be served (e.g., a reserved address).  Type (2)
              is reserved for BOOTP only devices, while type (3) is reserved
              for DHCP only devices.  A type of bootp-or-dhcp (4) can be
              offered to any type of client."
           ::= { dhcpv4ServerClientEntry 6 }
     
        dhcpv4ServerClientServedProtocol  OBJECT-TYPE
           SYNTAX      INTEGER {
              none(1),
              bootp(2),
              dhcp(3)
           }
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The type of protocol that was used when this address was
              assigned.  This object will have the value of none (1) if the
              address has not been served."
           ::= { dhcpv4ServerClientEntry 7 }
     
        dhcpv4ServerClientPhysicalAddress  OBJECT-TYPE
           SYNTAX      Dhcpv4PhysicalAddress
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The hardware type and hardware address of the client that has
              been assigned this lease.  The first octet of this object
              contains the hardware type from the 'htype' field of the BOOTP
     
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              packet and the remaining octets contain the hardware address
              from the 'chaddr' field of the BOOTP packet.  This object MAY
              be empty if the address has not been previously served."
           ::= { dhcpv4ServerClientEntry 8 }
     
        dhcpv4ServerClientClientId  OBJECT-TYPE
           SYNTAX      OCTET STRING (SIZE(0..255))
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The client-id of the client that has been assigned this
              lease.  The client-id is the value specified in option 61
              (client-id option) when the lease was assigned.  This object
              MAY be empty if the lease has not been previously assigned or
              if the client-id option was not specified when the address was
              assigned."
           ::= { dhcpv4ServerClientEntry 9 }
     
        dhcpv4ServerClientHostName  OBJECT-TYPE
           SYNTAX      SnmpAdminString (SIZE(1..255))
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The host name (DHCP option 12) the client is configured to
              use, or if no host name was configured then the host name that
              the client supplied when requesting an address.  While this
              object has a maximum size of 255 octets, a Fully-Qualified
              Domain Name (FQDN) consisting of a Host Name part and a Domain
              Name part is currently limited to 255 octets.  Therefore, the
              sum of the string lengths for this object and the
              dhcpv4ServerClientDomainName MUST be, in practice, less than
              256 octets."
           ::= { dhcpv4ServerClientEntry 10 }
     
        dhcpv4ServerClientDomainName  OBJECT-TYPE
           SYNTAX      SnmpAdminString (SIZE(1..255))
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The domain name (DHCP option 15) assigned to the client.
              While this object has a maximum size of 255 octets, a Fully-
              Qualified Domain Name (FQDN) consisting of a Host Name part
              and a Domain Name part is currently limited to 255 octets,
              less the separator ('.') character.  Therefore, the sum of the
              string lengths for this object and the
              dhcpv4ServerClientHostName MUST be, in practice, less than 256
              octets."
           ::= { dhcpv4ServerClientEntry 11 }
     
     
     
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        -- dhcpv4ServerNotifyObjects Group
     
        dhcpv4ServerNotifyDuplicateIpAddr  OBJECT-TYPE
           SYNTAX      InetAddressIPv4
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The IPv4 address found to be a duplicate.  Duplicates are
              detected by servers, which issue an ICMP ECHOREQUEST prior to
              offering an IPv4 address lease, or by a client issuing a
              gratuitous ARP message and reported through a DHCPDECLINE
              message."
           ::= { dhcpv4ServerNotifyObjects 1 }
     
        dhcpv4ServerNotifyDuplicateMac  OBJECT-TYPE
           SYNTAX      Dhcpv4PhysicalAddress
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The offending MAC address which caused a duplicate IPv4
              address to be detected, if captured by the server, else 00-00-
              00-00-00-00."
           ::= { dhcpv4ServerNotifyObjects 2 }
     
        dhcpv4ServerNotifyClientOrServerDetected  OBJECT-TYPE
           SYNTAX      INTEGER {
              client(1),
              server(2)
           }
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "Duplicate IPv4 addresses can be detected either by a server,
              using an ICMP ECHO message, or by a client using ARP.  This
              object is set by the server to (1) if the client used
              DHCPDECLINE to mark the offered address as in-use, or to (2)
              if the server discovered the address in use by some client
              before offering it."
           ::= { dhcpv4ServerNotifyObjects 3 }
     
        dhcpv4ServerNotifyServerStart  OBJECT-TYPE
           SYNTAX      DateAndTime
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The date and time when the server began operation."
           ::= { dhcpv4ServerNotifyObjects 4 }
     
        dhcpv4ServerNotifyServerStop  OBJECT-TYPE
           SYNTAX      DateAndTime
     
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           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The date and time when the server ceased operation."
           ::= { dhcpv4ServerNotifyObjects 5 }
     
     
        -- Notifications
     
        dhcpv4ServerNotificationPrefix  OBJECT IDENTIFIER
        ::= { dhcpv4Server 2 }
     
        dhcpv4ServerNotifications OBJECT IDENTIFIER
        ::= { dhcpv4ServerNotificationPrefix 0 }
     
        dhcpv4ServerFreeAddressLow  NOTIFICATION-TYPE
           OBJECTS {
              dhcpv4ServerSharedNetFreeAddrLowThreshold,
              dhcpv4ServerSharedNetFreeAddresses
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that the number of available IPv4
              addresses for a particular shared network has fallen below the
              value of dhcpv4ServerSharedNetFreeAddrLowThreshold for that
              shared network."
        ::= { dhcpv4ServerNotifications 1 }
     
        dhcpv4ServerFreeAddressHigh  NOTIFICATION-TYPE
           OBJECTS {
              dhcpv4ServerSharedNetFreeAddrHighThreshold,
              dhcpv4ServerSharedNetFreeAddresses
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that the number of available IPv4
              addresses for a particular shared network has risen above the
              value of dhcpv4ServerSharedNetFreeAddrHighThreshold for that
              shared network."
        ::= { dhcpv4ServerNotifications 2 }
     
        dhcpv4ServerStartTime  NOTIFICATION-TYPE
           OBJECTS     { dhcpv4ServerNotifyServerStart }
           STATUS      current
           DESCRIPTION
              "This notification signifies that the server of the specified
              type has started on the host from which this notification has
              been sent."
        ::= { dhcpv4ServerNotifications 3 }
     
     
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        dhcpv4ServerStopTime  NOTIFICATION-TYPE
           OBJECTS  { dhcpv4ServerNotifyServerStop }
           STATUS         current
           DESCRIPTION
              "This notification signifies that the server of the specified
              type has stopped normally on the host from which this
              notification has been sent."
        ::= { dhcpv4ServerNotifications 4 }
     
        dhcpv4ServerDuplicateAddress NOTIFICATION-TYPE
           OBJECTS {
              dhcpv4ServerNotifyDuplicateIpAddr,
              dhcpv4ServerNotifyDuplicateMac,
              dhcpv4ServerNotifyClientOrServerDetected
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that a duplicate IPv4 address has
              been detected.  The DHCP server can detect this condition
              through the ping-before-offer mechanism.  Alternatively, the
              client may have sent a DHCPDECLINE back to the server; this is
              assumed to be the result of the client detecting that the
              address was in use.  In either case, the DHCP server marks the
              IPv4 address as unavailable for leasing to clients.  The
              dhcpv4ServerNotifyClientOrServerDetected object indicates
              whether the client or server detected this condition."
        ::= { dhcpv4ServerNotifications 5 }
     
     
     
        -- Conformance
     
        dhcpv4ServerConformance  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "DHCP server conformance objects are all defined in this
              branch."
           ::= { dhcpv4Server 3 }
     
        dhcpv4ServerCompliances  OBJECT IDENTIFIER
        ::= { dhcpv4ServerConformance 1 }
     
        dhcpv4ServerGroups  OBJECT IDENTIFIER
        ::= { dhcpv4ServerConformance 2 }
     
     
        -- Compliance groups
     
        dhcpv4ServerCompliance MODULE-COMPLIANCE
           STATUS      current
     
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           DESCRIPTION
              "This group describes the requirements for conformance to the
              DHCP Server MIB.  A DHCPv4 server implementation is only
              REQUIRED to support IPv4 addresses.  In particular, this
              comment applies to the following objects with MAX-ACCESS not-
              accessible:
                 dhcpv4ServerSubnet
                 dhcpv4ServerRangeStart
                 dhcpv4ServerRangeEnd
                 dhcpv4ServerClient."
           MODULE -- this module
           MANDATORY-GROUPS {
              dhcpv4ServerSystemObjects,
              bootpCounterObjects,
              dhcpv4CounterObjects,
              dhcpv4ServerSharedNetObjects,
              dhcpv4ServerSubnetObjects,
              dhcpv4ServerRangeObjects,
              dhcpv4ServerClientObjects,
              dhcpv4ServerNotifyObjectsGroup,
              dhcpv4ServerNotificationsGroup
           }
        ::= { dhcpv4ServerCompliances 1 }
     
     
        -- Object groups
     
        dhcpv4ServerSystemObjects OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerSystemDescr,
              dhcpv4ServerSystemObjectID
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerSystemObjects group."
        ::= { dhcpv4ServerGroups 1 }
     
        bootpCounterObjects OBJECT-GROUP
           OBJECTS {
              bootpCountRequests,
              bootpCountInvalids,
              bootpCountReplies,
              bootpCountDroppedUnknownClients,
              bootpCountDroppedNotServingSubnet
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the bootpBounterObjects group."
        ::= { dhcpv4ServerGroups 2 }
     
     
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        dhcpv4CounterObjects  OBJECT-GROUP
           OBJECTS {
              dhcpv4CountDiscovers,
              dhcpv4CountOffers,
              dhcpv4CountRequests,
              dhcpv4CountDeclines,
              dhcpv4CountAcks,
              dhcpv4CountNaks,
              dhcpv4CountReleases,
              dhcpv4CountInforms,
              dhcpv4CountForcedRenews,
              dhcpv4CountInvalids,
              dhcpv4CountDroppedUnknownClient,
              dhcpv4CountDroppedNotServingSubnet
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4CounterObjects group."
        ::= { dhcpv4ServerGroups 3 }
     
        dhcpv4ServerSharedNetObjects  OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerSharedNetFreeAddrLowThreshold,
              dhcpv4ServerSharedNetFreeAddrHighThreshold,
              dhcpv4ServerSharedNetFreeAddresses,
              dhcpv4ServerSharedNetReservedAddresses,
              dhcpv4ServerSharedNetTotalAddresses
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerSharedNetObjects group."
           ::= { dhcpv4ServerGroups 4 }
     
        dhcpv4ServerSubnetObjects  OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerSubnetMask,
              dhcpv4ServerSubnetSharedNetworkName,
              dhcpv4ServerSubnetFreeAddrLowThreshold,
              dhcpv4ServerSubnetFreeAddrHighThreshold,
              dhcpv4ServerSubnetFreeAddresses
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerSubnetObjects group."
           ::= { dhcpv4ServerGroups 5 }
     
        dhcpv4ServerRangeObjects  OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerRangeSubnetMask,
              dhcpv4ServerRangeInUse,
     
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              dhcpv4ServerRangeOutstandingOffers
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerRangeObjects group."
           ::= { dhcpv4ServerGroups 6 }
     
        dhcpv4ServerClientObjects  OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerClientSubnetMask,
              dhcpv4ServerClientRange,
              dhcpv4ServerClientLeaseType,
              dhcpv4ServerClientTimeRemaining,
              dhcpv4ServerClientAllowedProtocol,
              dhcpv4ServerClientServedProtocol,
              dhcpv4ServerClientPhysicalAddress,
              dhcpv4ServerClientClientId,
              dhcpv4ServerClientHostName,
              dhcpv4ServerClientDomainName
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerClientObjects group."
           ::= { dhcpv4ServerGroups 7 }
     
        dhcpv4ServerNotifyObjectsGroup  OBJECT-GROUP
           OBJECTS {
              dhcpv4ServerNotifyDuplicateIpAddr,
              dhcpv4ServerNotifyDuplicateMac,
              dhcpv4ServerNotifyClientOrServerDetected,
              dhcpv4ServerNotifyServerStart,
              dhcpv4ServerNotifyServerStop
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpv4ServerNotifyObjects group."
           ::= { dhcpv4ServerGroups 8 }
     
        dhcpv4ServerNotificationsGroup  NOTIFICATION-GROUP
           NOTIFICATIONS {
              dhcpv4ServerFreeAddressLow,
              dhcpv4ServerFreeAddressHigh,
              dhcpv4ServerStartTime,
              dhcpv4ServerStopTime,
              dhcpv4ServerDuplicateAddress
           }
           STATUS      current
           DESCRIPTION
              "Notifications belonging to the dhcpv4ServerNotifications
              group."
     
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           ::= { dhcpv4ServerGroups 9 }
     
        END
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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     5. Intellectual Property
     
        The IETF takes no position regarding the validity or scope of any
        intellectual property or other rights that might be claimed to
        pertain to the implementation or use of the technology described in
        this document or the extent to which any license under such rights
        might or might not be available; neither does it represent that it
        has made any effort to identify any such rights.  Information on the
        IETF's procedures with respect to rights in standards-track and
        standards-related documentation can be found in BCP-11.
     
        Copies of claims of rights made available for publication and any
        assurances of licenses to be made available, or the result of an
        attempt made to obtain a general license or permission for the use
        of such proprietary rights by implementers or users of this
        specification can be obtained from the IETF Secretariat.
     
        The IETF invites any interested party to bring to its attention any
        copyrights, patents or patent applications, or other proprietary
        rights that may cover technology that may be required to practice
        this standard.  Please address the information to the IETF Executive
        Director.
     
     
     6. Acknowledgements
     
        This document is the result of work undertaken by the DHCP working
        group.  The editors would like to particularly acknowledge the
        development team from Carnegie-Mellon University whose work creating
        a private MIB for their DHCP server inspired the development of this
        proposal.  In particular, many thanks to Ryan Troll who provided a
        great deal of useful feedback during the initial development of this
        MIB, and to Rich Woundy for his excellent suggestions that helped
        bring the work to closure.
     
     
     7. IANA Considerations
     
        IANA MUST fill in the value of the RFC number when it is assigned to
        this memo.  It is represented as "xxxx" in the DESCRIPTION section
        of MODULE-IDENTITY.
     
        One specific value for a MIB object requires completion before this
        memo can advance to RFC status.  It is:
     
          o OID value for "dhcp" -- see MODULE-IDENTITY
     
     
     
     
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     8. Security Considerations
     
        There are no management objects defined in this MIB that have a MAX-
        ACCESS clause of read-write or read-create.  Such objects may be
        considered sensitive or vulnerable in some environments.  The
        support for SET operations in a non-secure environment without
        proper protection can have a negative effect on network operations.
        Therefore, if this MIB is implemented correctly, there is no risk
        that an intruder can alter or create any management objects of this
        MIB via direct SNMP SET operations.
     
        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:
     
          o  dhcpv4ServerRangeTable
     
          o  dhcpv4ServerClientTable
     
        These two objects, in conjunction, provide an observer with a
        current view of the available and assigned addresses allocated by
        this server.  Such knowledge can be used to manually configure a
        host computer with a valid IPv4 address for the network managed by
        the DHCP server.  This could be part of either a Theft of Service
        scheme or a Denial of Service attack wherein rogue (pseudo-)hosts
        simply claim and defend IPv4 addresses either to subvert accounting
        for their use or to disrupt the network for legitimate hosts.
     
        It is thus important to control even GET access to these objects and
        possibly to even encrypt the values of these objects when sending
        them over the network via SNMP.  Not all versions of SNMP provide
        features for such a secure environment.
     
        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.
     
        It is RECOMMENDED that the implementers consider the security
        features as provided by the SNMPv3 framework (see [RFC3410], section
        8), including full support for the SNMPv3 cryptographic mechanisms
        (for authentication and privacy).
     
        Further, deployment of SNMP versions prior to SNMPv3 is NOT
        RECOMMENDED.  Instead, it is RECOMMENDED to deploy SNMPv3 and to
     
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        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.
     
        Denial of Service attacks on a DHCP server are conceivable by
        flooding the SNMP (sub-)agent with requests, tying up host system
        and server resources processing SNMP messages.  The authors know of
        no way to wholly prevent such attacks, but have attempted to
        construct relatively simple tables to minimize the work required to
        respond to messages.
     
     
     9. References
     
        One normative reference is currently an Internet-Draft, nearly ready
        for Working Group Last Call.  This reference MUST be updated when
        the draft advances to RFC status.
     
     
     9.1. Normative References
     
       [RFC2131] Droms, R., "Dynamic Host Configuration Protocol," RFC 2131,
          March 1997.
     
       [RFC2132] Alexander, S. and Droms, R., "DHCP Options and BOOTP Vendor
          Extensions," RFC 2132, March 1997.
     
       [RFC2578] Case, J., McCloghrie, K., Perkins, D., Rose, M.,
          Schoenwaelder, J., and S. Waldbusser, "Structure of Management
          Information for Version 2 of the Simple Network Management
          Protocol (SNMPv2)," RFC 2578, April 1999.
     
       [RFC2579] Case, J., McCloghrie, K., Rose, M., Schoenwaelder, J., and
          S. Waldbusser, "Textual Conventions for Version 2 of the Simple
          Network Management Protocol (SNMPv2)," RFC 2579, April 1999.
     
       [RFC2580] Case, J., McCloghrie, K., Rose, M., Schoenwaelder, J., and
          S. Waldbusser, "Conformance Statements for Version 2 of the Simple
          Network Management Protocol (SNMPv2)," RFC 2580, April 1999.
     
       [RFC3203], Yves T'Joens and Christian Hublet, Peter De Schrijver,
          "The DHCP Reconfigure Extension," July 2001
     
     
     9.2. Informative References
     
       [RFC1123] R. Braden, "Requirements for Internet Hosts -- Application
          and Support," RFC 1123, October 1989.
     
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       [RFC3410] Case, J., Mundy, R., Partain, D. and B. Stewart,
          "Introduction and Applicability Statements for Internet-Standard
          Management Framework", RFC 3410, December 2002.
     
     
     10. Editors' Addresses
     
        Richard Barr Hibbs
        952 Sanchez Street
        San Francisco, California 94114-3362
        USA
     
        Phone:  +1-(415)-648-3920
        Fax:  +1-(415)-648-9017
        Email:  rbhibbs@pacbell.net
     
        Glenn Waters
        Nortel Networks
        310-875 Carling Avenue,
        Ottawa, Ontario K1S 5P1
        Canada
     
        Phone:  +1-(613)-798-4925
        Email:  gww@NortelNetworks.com
     
     
     11. Full Copyright Statement
     
        Copyright (C), 2004, The Internet Society.  All Rights Reserved.
     
        This document and translations of it may be copied and furnished to
        others, and derivative works that comment on or otherwise explain it
        or assist in its implementation may be prepared, copied, published
        and distributed, in whole or in part, without restriction of any
        kind, provided that the above copyright notice and this paragraph
        are included on all such copies and derivative works.  However, this
        document itself may not be modified in any way, such as by removing
        the copyright notice or references to the Internet Society or other
        Internet organizations, except as needed for the purpose of
        developing Internet standards in which case the procedures for
        copyrights defined in the Internet Standards process must be
        followed, or as required to translate it into languages other than
        English.
     
        The limited permissions granted above are perpetual and will not be
        revoked by the Internet Society or its successors or assigns.
     
        This document and the information contained herein is provided on an
        "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
        TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
     
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        BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
        HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
        MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
     
        Acknowledgement
     
        Funding for the RFC Editor function is currently provided by the
        Internet Society.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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