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     Network Working Group                                      Barr Hibbs
     INTERNET-DRAFT                                       (no affiliation)
     Category:  Standards Track                               Glenn Waters
                                                           Nortel Networks
                                                             February 2002
     
     
                Dynamic Host Configuration Protocol (DHCP) Server MIB
     
     
                         <draft-ietf-dhc-server-mib-06.txt>
                   Saved Thursday, February 14, 2002, 11:26:01 AM
     
     
     
     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 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."
     
        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) 2002, 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 (DHCP) and
        Bootstrap Protocol (BOOTP) servers.
     
     
     
     
     
     
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     Table of Contents
     
        1. Introduction...................................................2
        2. Overview.......................................................3
          2.1. Relationship to Other MIBs.................................4
            2.1.1. DHCP MIB Extensions...................................4
            2.1.2. Host System MIB Extensions............................4
            2.1.3. DHCPv6 Server MIB Extensions..........................4
            2.1.4. DHCP Client MIB Extensions............................5
            2.1.5. DHCP Relay Agent MIB Extensions.......................5
          2.2. Textual Conventions Introduced in this MIB.................5
            2.2.1. DhcpTimeInterval......................................5
            2.2.2. HardwareAddressType...................................5
            2.2.3. HardwareAddressLength.................................5
            2.2.4. MacAddress............................................5
            2.2.5. PhysicalAddress.......................................5
            2.2.6. DhcpLabel.............................................6
          2.3. BOOTP and DHCP Counter Groups..............................6
          2.4. BOOTP and DHCP Optional Statistics Group...................6
          2.5. Response Times and ICMP Echo...............................8
        3. Definitions....................................................8
        4. Intellectual Property.........................................39
        5. Notes.........................................................40
          5.1. Issues....................................................40
          5.2. Changes from Prior Drafts.................................41
        6. Acknowledgements..............................................42
        7. Security Considerations.......................................42
        8. References....................................................43
        9. Editors' Addresses............................................44
        10. Full Copyright Statement.....................................44
     
     
     
     1. Introduction
     
        This memo was produced by 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 DHCP and Bootstrap Protocol
        (BOOTP) servers implement.  Many implementations support both DHCP
        and BOOTP within a single server and hence this memo describes the
        MIB for both DHCP and BOOTP servers.
     
        This memo does not cover DHCP/BOOTP client nor relay agent MIB
        extensions:  these are possibly the subjects of future investigation
        [see discussion in section 2.1.]  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.
     
     
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        Provision is also made for Standards-Track additions to the DHCP
        Message Type (option 61.)
     
        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 through the use of 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 document [RFC2119].
     
     
     2. Overview
     
        In the tradition of the Simple Network Management Protocol (SNMP) the
        minimum number of objects possible are 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 may be derived.
     
        The examples provided in sections 2.3 through 2.5 are not meant to be
        comprehensive but are illustrative of the potential uses of the
        objects defined by this MIB.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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     2.1. Relationship to Other MIBs
     
     
     2.1.1. DHCP MIB Extensions
     
        The DHCP MIB extensions will 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 MIBs will share a common branching point, but are independently
        defined.
     
     
     2.1.2. 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.
     
     
     2.1.3. DHCPv6 Server MIB Extensions
     
        When this set of MIB extensions is developed, it will share a common
        branch point in the MIB tree with the other DHCP MIB Extensions.
     
     
     
     
     
     
     
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     2.1.4. DHCP Client 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.
     
     
     2.1.5. 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.
     
     
     2.2. Textual Conventions Introduced in this MIB
     
        Severaal conceptual data types have been introduced as textual
        conventions in this DHCP MIB document.  These additions will
        facilitate the common understanding of information used by the DHCP
        server.  No changes to the SMI or the SNMP are necessary to support
        these conventions.
     
     
     2.2.1. DhcpTimeInterval
     
        This data type measures time intervals since the beginning of some
        epoch in milliseconds.
     
     
     2.2.2. HardwareAddressType
     
        This data type contains the type of hardware address represented by
        MacAddress, as defined for ARP messages.
     
     
     2.2.3. HardwareAddressLength
     
        The length in octets of MacAddress is contained in this type.
     
     
     2.2.4. MacAddress
     
        The actual layer 1 hardware address is contained in this data type.
     
     
     2.2.5. PhysicalAddress
     
        This data type combines the hardware type octet with the length and
        hardware (NIC or MAC) address to produce a unique address type.
     
     
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     2.2.6. DhcpLabel
     
        This data type contains labels used as identifiers by DHCP servers.
     
     
     2.3. BOOTP and DHCP Counter Groups
     
        This section describes some of the management information that may be
        derived from the objects provided in the counter groups.
     
        The total number of valid DHCP packets received by the server is
        computed as the sum of the dhcpCountDiscovers, dhcpCountRequests,
        dhcpCountReleases, dhcpCountDeclines, dhcpCountInforms and
        dhcpCountLeaseQueries objects.  The total number of valid packets
        (BOOTP and DHCP) received is computed as the total number of valid
        DHCP packets plus the value of the bootpCountRequests object.  The
        total number of packets received is computed as the total number of
        valid packets plus the sum of bootpCountInvalids and
        dhcpCountInvalids.
     
        Similar to the received computations, the total number of DHCP
        packets sent by the server is computed as the sum of the
        dhcpCountOffers, dhcpCountAcks, dhcpCountNacks,
        dhcpCountForcedRenews, dhcpCountKnowns, and dhcpCountUnknowns
        objects.  The number of packets (BOOTP and DHCP) sent by the server
        is computed as the total number of DHCP packets sent plus the value
        of the bootpCountReplies object.
     
     
     2.4. BOOTP and DHCP Optional Statistics Group
     
        This section describes some of the management information that may be
        derived from the objects provided in the optional statistics group.
     
        Given time 1 (t1) and time 2 (t2) greater than t1, the mean inter-
        arrival time of valid DHCP messages for the interval t1 to t2 can be
        computed as (dhcpStatLastArrivalTime at t2 minus
        dhcpStatLastArrivalTime at t1) divided by (valid DHCP received packet
        count at t2 minus valid DHCP received packet count at t1).
     
        Under the simplifying assumption that the capture of packet counts
        and times is discontinuous (that is, for the measurement interval the
        captured data represents the complete set for the server) the
        variance of the mean may be computed as
        (dhcpStatSumSquaresArrivalTime at t2 less
        dhcpStatSumSquaresArrivalTime at t1) divided by (valid DHCP received
        packet count at t2 less valid DHCP received packet count at t1).
        Standard deviation of the mean is the square root of the variance.
     
     
     
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        Calculation of statistics for message response time is entirely
        similar to the calculations for inter-arrival time, except that the
        response time objects are used for the calculations.
     
        Calculation of statistics for BOOTP is similar to the calculations
        for DHCP, except that the similar objects from the
        bootpOptionalStatistics group are used instead of the objects from
        dhcpOptionalStatistics group.server Configuration Group
     
        The server configuration group contains objects that describe the
        configuration information that is contained in the server.  Some of
        the configuration information is static (e.g., a statically
        configured IP 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.
        Mechanisms outside of the SNMP are currently in use (e.g., vendor
        defined solutions) and are being standardized (e.g., the Directory
        Enabled Networks [DEN] initiative) to update a server's
        configuration.
     
        The configuration information defines a minimal set of information
        that most servers should be able to provide.  Each row of the
        serverSubnetTable lists the subnet, the subnet mask, and the subnet
        that is equivalent to this subnet.  Equivalence is defined as more
        than one subnet being present on the same network segment as some
        other subnet.
     
        The serverRangeTable lists the start and end IP addresses of the
        ranges and the subnet of which the range is a member.  The
        serverRangeInUse 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 by taking the difference of
        the serverRangeStart and serverRangeEnd objects.
     
        The serverAddressTable provides information about the static and
        dynamic addresses that the server contains in its configuration.
        Addresses may 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 for
            which the lease time has expired, but is retained by the server
            for possible future use by the same client;
     
     
     
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          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
            which have been declined (i.e., through a DHCPDECLINE) by a
            client or those which have responded to an ICMP echo before they
            were assigned.
     
        The protocol used to allocate the address may be determined from the
        serverAddressServedProtocol object.  This object indicates whether
        the address has never been served, or whether BOOTP or DHCP was used
        to allocate the address.
     
     
     2.5. Response Times and ICMP Echo
     
        According to [RFC2131], servers SHOULD try to determine if an address
        is in use before assigning it.  Some servers choose not to perform
        this check, letting the client determine for itself if the address is
        in use.  Other servers perform an ICMP echo (Ping) just prior to
        assigning an address.  Servers that perform a Ping before responding
        to a DHCPDISCOVER should not include in the response time the time
        from when the Ping was transmitted until the time that either a
        response was received or that the server timed out waiting for a
        response.
     
     
     3. Definitions
     
     
        -- definitions for a DHCP (Dynamic Host Configuration Protocol)
        server
     
        DHCP-SERVER-MIB DEFINITIONS ::= BEGIN
     
        IMPORTS
           Counter64, Counter32, Gauge32, Unsigned32, mib-2, MODULE-IDENTITY,
           OBJECT-TYPE,  OBJECT-IDENTITY, IpAddress
              FROM SNMPv2-SMI
     
           TEXTUAL-CONVENTION, RowStatus, DisplayString, TruthValue,
           DateAndTime FROM SNMPv2-TC
     
           MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
     
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              FROM SNMPv2-CONF;
     
        dhcp  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "The dhcp branch in the standard network management framework."
           ::= { mib-2 99 }  -- IANA will make official assignment
     
        serverMIB  MODULE-IDENTITY
           LAST-UPDATED   "2002-02-14 11:26"
           ORGANIZATION   "IETF DHC Working Group"
           CONTACT-INFO
              "        Richard Barr Hibbs
              Postal:  952 Sanchex 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
              4(IPv4).  This MIB does not include support for Dynamic DNS
              (DDNS) updating nor for the DHCP Failover Protocol."
           ::= { dhcp 1 }
     
        serverMIBObjects  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "DHCP Server MIB objects are all defined in this branch."
        ::= { serverMIB 1 }
     
        serverSystem  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Group of objects that are related to the overall system."
        ::= { serverMIBObjects 1 }
     
        bootpCounters  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
     
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              "Group of objects that count various BOOTP events."
        ::= { serverMIBObjects 2 }
     
        dhcpCounters  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Group of objects that count various DHCP events."
        ::= { serverMIBObjects 3 }
     
        bootpOptionalStatistics  OBJECT-IDENTITY -- /*renamed*/
           STATUS      current
           DESCRIPTION
              "Group of objects that measure various BOOTP statistics."
        ::= { serverMIBObjects 4 }
     
        dhcpOptionalStatistics  OBJECT-IDENTITY  -- /*renamed*/
           STATUS      current
           DESCRIPTION
              "Group of objects that measure various DHCP statistics."
        ::= { serverMIBObjects 5 }
     
        serverConfiguration  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Objects that contain pre-configured and dynamic configuration
              information."
        ::= { serverMIBObjects 6 }
     
        bootpClients  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Objects that map bootp clients to IP addresses."
        ::= { serverMIBObjects 7 }
     
        dhcpClients  OBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "Objects that map DHCP clients to IP addresses."
        ::= { serverMIBObjects 8 }
     
     
        -- Textual conventions defined by this memo
     
        DhcpTimeInterval ::= TEXTUAL-CONVENTION
           SYNTAX      Unsigned32
           STATUS      current
           DESCRIPTION
              "The number of milliseconds that has elapsed since some epoch.
              Systems that cannot measure events to the millisecond
     
     
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              resolution SHOULD round this value to the next available
              resolution that the system supports."
     
        HardwareAddressType ::= TEXTUAL-CONVENTION
           SYNTAX         OCTET
           STATUS         current
           REFERENCE      "RFC 2131"
           DESCRIPTION
              "The value of the hardware type field, as used in ARP messages
              (e.g., 1 for Ethernet, 6 for token ring).  IANA maintains the
              list of registered numbers for this field."
     
        HardwareAddressLength ::= TEXTUAL-CONVENTION
           SYNTAX         OCTET
           STATUS         current
           REFERENCE      "RFC 2131"
           DESCRIPTION
              "The length in octets of the hardware address field (e.g., 6
              for Ethernet).  IANA maintains the list of registered numbers
              for this field."
     
        MacAddress ::= TEXTUAL-CONVENTION
           SYNTAX         OCTET STRING (SIZE (1..16))
           DISPLAY-HINT   "t,l,xx[:xx...]"
           STATUS         current
           REFERENCE      "RFC 2131"
           DESCRIPTION
              "A Layer 1 address, the hardware address of the MAC (Media
              Adapter Card) interface.  The address length is fixed for a
              given hardware address type, but varies by type."
     
        PhysicalAddress ::= TEXTUAL-CONVENTION
           SYNTAX         SEQUENCE OF {
              HardwareAddressType,
              HardwareAddressLength,
              MacAddress
           }
           DISPLAY-HINT   "t,l,xx[:xx...]"
           STATUS         current
           REFERENCE      "RFC 2131"
           DESCRIPTION
              "A Layer 1 address which includes the hardware type space as
              well as the usual MAC address.  This encoding is intended to
              mirror the representation of physical addresses in DHCP."
     
        DhcpLabel ::= TEXTUAL-CONVENTION
           SYNTAX         DisplayString (SIZE (1..100))
           DISPLAY-HINT
           STATUS         current
           DESCRIPTION
     
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        -- serverSystem Group
     
        serverSystemDescr  OBJECT-TYPE
           SYNTAX      DisplayString (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."
           ::= { serverSystem 1 }
     
        serverSystemObjectID  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
              'VeryBigServers, Inc.' is assigned the subtree
              1.3.6.1.4.1.4242, it may assign the identifier
              1.3.6.1.4.1.4242.1.1 to its `Hercules DHCP Server'."
           ::= { serverSystem 2 }
     
     
        -- dhcpCounters Group
     
        -- DHCP received packet counters
     
        dhcpCountDiscovers  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPDISCOVER (option 53 with value 1) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 1 }
     
        dhcpCountRequests  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
     
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              "The number of DHCPREQUEST (option 53 with value 3) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 2 }
     
        dhcpCountReleases  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPRELEASE (option 53 with value 7) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 3 }
     
        dhcpCountDeclines  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPDECLINE (option 53 with value 4) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 4 }
     
        dhcpCountInforms  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPINFORM (option 53 with value 8) packets
              received."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 5 }  -- /*renumbered*/
     
        dhcpCountLeaseQueries  OBJECT-TYPE  -- /*new*/
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPLEASEQUERY (option 53 with value TBD)
              packets received."
           REFERENCE
              "draft-ietf-dhc-leasequery-02.txt."
           ::= { dhcpCounters 6 }  -- /*new*/
     
     
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        -- DHCP sent packet counters
     
        dhcpCountOffers  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPOFFER (option 53 with value 2) packets
              sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 11 }  -- /*renumbered*/
     
        dhcpCountAcks  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPACK (option 53 with value 5) packets sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 12 }  -- /*renumbered*/
     
        dhcpCountNacks  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPNACK (option 53 with value 6) packets sent."
           REFERENCE
              "RFC2131; RFC2132, section 9.6."
           ::= { dhcpCounters 13 }  -- /*renumbered*/
     
        dhcpCountForcedRenews  OBJECT-TYPE  -- /*new*/
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPFORCERENEW (option 53 with value TBD)
              packets sent."
           REFERENCE
              "draft-ietf-dhc-pv4-reconfigure-06.txt."
           ::= { dhcpCounters 14 }  -- /*new*/
     
        dhcpCountKnowns  OBJECT-TYPE  -- /*new*/
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
     
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              "The number of DHCPKNOWN (option 53 with value TBD) packets
              sent."
           REFERENCE
              "draft-ietf-dhc-leasequery-02.txt."
           ::= { dhcpCounters 12 }  -- /*new*/
     
        dhcpCountUnknowns  OBJECT-TYPE  -- /*new*/
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The number of DHCPUNKNOWN (option 53 with value TBD) packets
              sent."
           REFERENCE
              "draft-ietf-dhc-leasequery-02.txt."
           ::= { dhcpCounters 13 }  -- /*new*/
     
     
        -- DHCP packet error counters
     
        dhcpCountInvalids  OBJECT-TYPE
           SYNTAX      Counter32
           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."
           ::= { dhcpCounters 17 }  -- /*renumbered*/
     
        dhcpCountDroppedUnknownClient  OBJECT-TYPE
           SYNTAX      Counter32
           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."
           ::= { dhcpCounters 18 }  -- /*renumbered*/
     
        dhcpCountDroppedNotServingSubnet  OBJECT-TYPE
           SYNTAX      Counter32
           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."
           ::= { dhcpCounters 19 }  -- /*renumbered*/
     
     
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        -- dhcpOptionalStatistics group
     
        dhcpStatMinArrivalInterval  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The minimum amount of time between receiving two DHCP
              messages.  A message is received at the server when the server
              is able to begin processing the message.  This typically occurs
              immediately after the message is read into server memory.  If
              no messages have been received, then this object contains a
              zero value."
           ::= { dhcpOptionalStatistics 1 }  -- /*renamed*/
     
        dhcpStatMaxArrivalInterval  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The maximum amount of time between receiving two DHCP
              messages.  A message is received at the server when the server
              is able to begin processing the message.  This typically occurs
              immediately after the message is read into server memory.  If
              no messages have been received, then this object contains a
              zero value."
           ::= { dhcpOptionalStatistics 2 }  -- /*renamed*/
     
        dhcpStatLastArrivalTime   OBJECT-TYPE
           SYNTAX DateAndTime
           MAX-ACCESSread-only
           STATUS current
           DESCRIPTION
              "The date and time that the last valid DHCP message was
              received by the server.  Invalid messages do not cause this
              value to change.  If no valid messages have been received, then
              this object contains a date and time that is all zero."
           ::= { dhcpOptionalStatistics 3 }
     
        dhcpStatSumSquaresArrivalTime  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the squared DHCP packet inter-arrival times in
              microseconds.  This value may be used to compute the variance
              and standard deviation of the DHCP arrival times.  Note that a
              microsecond resolution of this object requires a clock
     
     
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              resolution to the millisecond since the square of a millisecond
              value produces a value with microsecond resolution."
           ::= { dhcpOptionalStatistics 4 }-- /*renamed*/
     
        dhcpStatMinResponseTime  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The smallest time interval measured as the difference between
              the arrival of a DHCP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
           ::= { dhcpOptionalStatistics 5 }-- /*renamed*/
     
        dhcpStatMaxResponseTime  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The largest time interval measured as the difference between
              the arrival of a DHCP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
           ::= { dhcpOptionalStatistics 6 }-- /*renamed*/
     
        dhcpStatSumResponseTime  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the response time intervals in milliseconds where a
              response time interval is measured as the difference between
              the arrival of a DHCP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
     
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              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
           ::= { dhcpOptionalStatistics 7 }-- /*renamed*/
     
        dhcpStatSumSquaresResponseTime  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the squared DHCP packet response times in micro-
              seconds.  This value may be used to compute the variance and
              standard deviation of the DHCP response times.  Note that a
              microsecond resolution of this object requires a clock
              resolution to the millisecond since the square of a millisecond
              value produces a value with microsecond resolution."
           ::= { dhcpOptionalStatistics 8 }-- /*renamed*/
     
     
        -- bootpCounters Group
     
        bootpCountRequests  OBJECT-TYPE
           SYNTAX      Counter32
           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-1541."
           ::= { bootpCounters 1 }-- /*renamed*/
     
        bootpCountInvalids  OBJECT-TYPE
           SYNTAX      Counter32
           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 }-- /*renamed*/
     
        bootpCountReplies  OBJECT-TYPE
           SYNTAX      Counter32
     
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           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-1541."
           ::= { bootpCounters 3 }-- /*renamed*/
     
        bootpCountDroppedUnknownClients  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "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 }-- /*renamed*/
     
        bootpCountDroppedNotServingSubnet  OBJECT-TYPE
           SYNTAX      Counter32
           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 }-- /*renamed*/
     
     
        -- bootpOptionalStatistics group
     
        bootpStatMinArrivalInterval  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The minimum amount of time between receiving two BOOTP
              messages.  A message is received at the server when the server
              is able to begin processing the message.  This typically occurs
              immediately after the message is read into server memory.  If
              no messages have been received, then this object contains a
              zero value."
           ::= { bootpOptionalStatistics 1 }-- /*renamed*/
     
        bootpStatMaxArrivalInterval  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
     
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           DESCRIPTION
              "The maximum amount of time between receiving two BOOTP
              messages.  A message is received at the server when the server
              is able to begin processing the message.  This typically occurs
              immediately after the message is read into server memory.  If
              no messages have been received, then this object contains a
              zero value."
           ::= { bootpOptionalStatistics 2 }-- /*renamed*/
     
        bootpStatLastArrivalTime   OBJECT-TYPE
           SYNTAX      DateAndTime
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The date and time that the last valid BOOTP message was
              received by the server.  Invalid messages do not cause this
              value to change.  If valid no messages have been received, then
              this object contains a date and time that is all zero."
           ::= { bootOptionalpStatistics 3 }  -- /*renamed*/
     
        bootpStatSumSquaresArrivalTime  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the squared BOOTP packet inter-arrival times in
              microseconds.  This value may be used to compute the variance
              and standard deviation of the BOOTP arrival times.  Note that a
              microsecond resolution of this object requires a clock
              resolution to the millisecond since the square of a millisecond
              value produces a value with microsecond resolution."
           ::= { bootpOptionalStatistics 4 }-- /*renamed*/
     
        bootpStatMinResponseTime  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The smallest time interval measured as the difference between
              the arrival of a BOOTP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
     
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
     
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           ::= { bootpOptionalStatistics 5 }-- /*renamed*/
     
        bootpStatMaxResponseTime  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The largest time interval measured as the difference between
              the arrival of a BOOTP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
     
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
           ::= { bootpOptionalStatistics 6 }-- /*renamed*/
     
        bootpStatSumResponseTime  OBJECT-TYPE
           SYNTAX      Counter32
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the response time intervals in milliseconds where a
              response time interval is measured as the difference between
              the arrival of a BOOTP message at the server and the successful
              transmission of the response to that message.  A message is
              received at the server when the server is able to begin
              processing the message.  A message is transmitted after the
              server has no further use for the message.  Note that the
              operating system may still have the message queued internally.
     
              The operating system queue time is not to be considered as part
              of the response time.  Invalid messages do not cause this value
              to change.  If no valid messages have been received, then this
              object contains a zero value."
           ::= { bootpOptionalStatistics 7 }-- /*renamed*/
     
        bootpStatSumSquaresResponseTime  OBJECT-TYPE
           SYNTAX      Counter64
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The sum of the squared BOOTP packet response times in micro-
              seconds.  This value may be used to compute the variance and
              standard deviation of the BOOTP response times.  Note that a
              microsecond resolution of this object requires a clock
     
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              resolution to the millisecond since the square of a millisecond
              value produces a value with microsecond resolution."
           ::= { bootpOptionalStatistics 8 }-- /*renamed*/
     
     
        -- server configurationgroup
     
        -- server shared network table
     
        serverSharedNetworkTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF serverSharedNetworkEntry
           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."
           ::= { serverConfiguration 1 }
     
        serverSharedNetworkEntry  OBJECT-TYPE
           SYNTAX      ServerSharedNetworkEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           INDEX       { serverSharedNetworkName }
           DESCRIPTION
              "A logical row in the serverSharedNetworkTable."
           ::= { serverSharedNetworkTable 1}
     
        ServerSharedNetworkEntry ::= SEQUENCE {
              serverSharedNetworkName                DhcpLabel,
              serverSharedNetworkFreeAddresses       Unsigned32,
              serverSharedNetworkReservedAddresses   Unsigned32,-- /*new*/
              serverSharedNetworkTotalAddresses      Unsigned32-- /*renamed*/
           }
     
        serverSharedNetworkName  OBJECT-TYPE
           SYNTAX      DhcpLabel-- /*modified*/
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The name of the shared network, which uniquely identifies an
              entry in the serverSharedNetworkTable."
           ::= { serverSharedNetworkEntry 1 }
     
        serverSharedNetworkFreeAddresses  OBJECT-TYPE-- /*renamed*/
           SYNTAX      Unsigned32
     
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           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IP 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."
           ::= { serverSharedNetworkEntry 2 }-- /*renumbered*/
     
        serverSharedNetworkReservedAddresses  OBJECT-TYPE-- /*new*/
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IP addresses which are reserved (not available
              for assignement) within this shared network.  If the server
              does not count reserved addresses by shared network segment,
              this value will be zero."
           ::= { serverSharedNetworkEntry 3 }
     
        serverSharedNetworkTotalAddresses  OBJECT-TYPE-- /*new*/
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The number of IP 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."
           ::= { serverSharedNetworkEntry 4 }
     
     
        -- server subnet table
     
        serverSubnetTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF serverSubnetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A list of subnets that are configured in this server."
           ::= { serverConfiguration 2 }
     
        serverSubnetEntry  OBJECT-TYPE
           SYNTAX      ServerSubnetEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           INDEX       { serverSubnet }
           DESCRIPTION
              "A logical row in the serverSubnetTable."
           ::= { serverSubnetTable 1 }
     
        ServerSubnetEntry ::= SEQUENCE {
     
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           serverSubnet                           IpAddress,
           serverSubnetMask                       IpAddress,
           serverSubnetSharedNetworkName          DhcpLabel,-- /*modified*/
           serverSubnetFreeAddressLowThreshold    Unsigned32,
           serverSubnetFreeAddressHighThreshold   Unsigned32,
           ServerSubnetFreeAddresses              Unsigned32  -- /*renamed*/
           }
     
        serverSubnet  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only-- /*changed*/
           STATUS      current
           DESCRIPTION
              "The IP address of the subnet."
           ::= { serverSubnetEntry 1 }
     
        serverSubnetMask  OBJECT-TYPE
           SYNTAX      IpAddress
           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."
           ::= { serverSubnetEntry 2 }
     
        serverSubnetSharedNetworkName  OBJECT-TYPE-- /*renamed*/
           SYNTAX      DhcpLabel-- /*modified*/
           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."
           ::= { serverSubnetEntry 3 }
     
        serverSubnetFreeAddressLowThreshold  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
              serverSubnetFreeAddressLowThreshold event is generated for this
              shared network.  No more serverSubnetFreeAddressLowThreshold
              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
              serverSubnetFreeAddressHighThreshold."
     
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           ::= { serverSubnetEntry 4 }
     
        serverSharedNetworkFreeAddressHighThreshold  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The high threshold for available free addresses in this
              subnet.  If a serverSubnetFreeAddressLowThreshold event has
              been generated for this subnet, and the value for available
              free addresses has exceeded the value of
              serverSubnetFreeAddressHighThreshold, then a
              serverFreeAddressessHigh event will be generated.  No more
              serverFreeAddressessHigh 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 serverSubnetFreeAddressHighThreshold."
           ::= { serverSubnetEntry 5 }
     
     
        -- server range table
     
        serverRangeTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF serverRangeEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "A list of ranges that are configured on this server."
           ::= { serverConfiguration 3 }
     
        serverRangeEntry  OBJECT-TYPE
           SYNTAX      ServerRangeEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           INDEX    { serverRangeStart }
           DESCRIPTION
              "A logical row in the serverRangeTable."
           ::= { serverRangeTable 1 }
     
        ServerRangeEntry ::= SEQUENCE {
           serverRangeStart              IpAddress,
           serverRangeEnd                IpAddress,
           serverRangeSubnetMask         IpAddress,
           serverRangeInUse              Gauge32,
           serverRangeOutstandingOffers  Gauge32
           }
     
        serverRangeStart  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only
     
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           STATUS      current
           DESCRIPTION
              "The IP address of the first address in the range.  The value
              of range start must be less than or equal to the value of range
              end."
           ::= { serverRangeEntry 1 }
     
        serverRangeEnd  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The IP address of the last address in the range.  The value of
              range end must be greater than or equal to the value of range
              start."
           ::= { serverRangeEntry 2 }
     
        serverRangeSubnetMask  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The subnet address mask for this range."
           ::= { serverRangeEntry 3 }
     
        serverRangeInUse  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)."
           ::= { serverRangeEntry 4 }
     
        serverRangeOutstandingOffers  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."
           ::= { serverRangeEntry 5 }
     
     
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        -- server address table
     
        serverAddressTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF serverAddressEntry
           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."
           ::= { serverConfiguration 4 }
     
        serverAddressEntry  OBJECT-TYPE
           SYNTAX      ServerAddressEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           INDEX       { serverAddress }
           DESCRIPTION
              "A logical row in the serverAddressTable."
           ::= { serverAddressTable 1 }
     
        ServerAddressEntry ::= SEQUENCE {
           serverAddress                 IpAddress,
           serverAddressSubnetMask       IpAddress,
           serverAddressRange            IpAddress,
           serverAddressType             INTEGER,
           serverAddressTimeRemaining    Unsigned32,
           serverAddressAllowedProtocol  INTEGER,
           serverAddressServedProtocol   INTEGER,
           serverAddressMacAddress       OCTET STRING,
           serverAddressClientId         OCTET STRING,
           serverAddressHostName         DisplayString,
           serverAddressDomainName       DisplayString
           }
     
        serverAddress  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The IP address of the entry."
           ::= { serverAddressEntry 1 }
     
        serverAddressSubnetMask  OBJECT-TYPE
           SYNTAX      IpAddress
     
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           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 IP address, must be configured on
              this server and appear as a row in the dhcpSubnetTable."
           ::= { serverAddressEntry 2 }
     
        serverAddressRange  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The starting IP address (serverRangeStart 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."
           ::= { serverAddressEntry 3 }
     
        serverAddressType  OBJECT-TYPE
           SYNTAX      INTEGER {
               static(1),
               dynamic(2),
               expired(3),  -- /*new*/
               configuration-reserved(4),  -- /*renumbered*/
               server-reserved(5)  -- /*renumbered*/
              }
           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 IP address or a DHCPDECLINE message
                    has been received for the IP address."
           ::= { serverAddressEntry 4 }
     
        serverAddressTimeRemaining  OBJECT-TYPE
           SYNTAX      Unsigned32
           MAX-ACCESS  read-only
     
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           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."
           ::= { serverAddressEntry 5 }
     
        serverAddressAllowedProtocol  OBJECT-TYPE
           SYNTAX      INTEGER {
              none(1),
              bootp(2),
              dhcp(3),
              bootp-or-dhcp(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) are
              reserved for BOOTP only devices, while type (3) are reserved
              for DHCP only devices.  A type of bootp-or-dhcp (4) may be
              offered to any type of client."
           ::= { serverAddressEntry 6 }
     
        serverAddressServedProtocol  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."
           ::= { serverAddressEntry 7 }
     
        serverAddressHardwareAddress  OBJECT-TYPE
           SYNTAX      PhysicalAddress
           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
              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."
     
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           ::= { serverAddressEntry 8 }
     
        serverAddressClientId  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."
           ::= { serverAddressEntry 9 }
     
        serverAddressHostName  OBJECT-TYPE
           SYNTAX      DisplayString (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
              serverAddressDomainName must, in practice, be less than 256
              octets."
           ::= { serverAddressEntry 10 }
     
        serverAddressDomainName  OBJECT-TYPE
           SYNTAX      DisplayString (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 serverAddressHostName must, in
              practice, be less than 256 octets."
           ::= { serverAddressEntry 11 }
     
     
        -- Server Client Table
     
        serverClientTable  OBJECT-TYPE
           SYNTAX      SEQUENCE OF serverClientEntry
           MAX-ACCESS  not-accessible
     
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           STATUS      current
           DESCRIPTION
              "A list of clients that are known by this server.  Details
              about the clients may be found by indexing into the
              serverAddressTable using the serverClientHardwareAddress and
              serverClientAddress objects.  This table is indexed first by
              the MAC address of the client and then by the subnet address on
              which the client resides.  The subnet is included as an index
              since a MAC address is only guaranteed to be unique within a
              subnet (i.e., a MAC address is not globally unique)."
           ::= { serverConfiguration 5 }
     
        serverClientEntry  OBJECT-TYPE
           SYNTAX      ServerClientEntry
           MAX-ACCESS  not-accessible
           STATUS      current
           INDEX    { serverClientHardwareAddress, serverClientAddress }
           DESCRIPTION
              "A logical row in the serverClientTable.  An entry in this
              table may be a client that requested an address but was refused
              (e.g., not authorized).Servers MAY track these types of clients
              if desired and may choose to remove such client entries using a
              server defined algorithm.  As an example, a server may choose
              to keep client request that does not map to an address for a
              one hour time period before removing that entry from this
              table."
           ::= { serverClientTable 1 }
     
        ServerClientEntry ::= SEQUENCE {
              serverClientHardwareAddress      PhysicalAddress
              serverClientSubnetMask           IpAddress,
              serverClientAddress              IpAddress,
              serverClientLastRequestTime      DateAndTime,
              serverClientLastRequestType      INTEGER,
              serverClientLastResponseType     INTEGER
           }
     
        serverClientHardwareAddress  OBJECT-TYPE
           SYNTAX      PhysicalAddress
           MAX-ACCESS  not-accessible
           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
              packet and the remaining octets contain the hardware address
              from the 'chaddr' field of the BOOTP packet."
           ::= { serverClientEntry 1 }
     
        serverClientSubnetMask  OBJECT-TYPE
     
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           SYNTAX      IpAddress
           MAX-ACCESS  not-accessible
           STATUS      current
           DESCRIPTION
              "The subnet mask (DHCP option 1) applied to
              serverClientAddress."
           ::= { serverClientEntry 2 }
     
        serverClientAddress  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The IP address of the entry.  May be used to index into the
              serverAddressTable.  May be 0.0.0.0 if an address is not
              associated with this client."
           ::= { serverClientEntry 3 }
     
        serverClientLastRequestTime  OBJECT-TYPE
           SYNTAX      DhcpTimeInterval
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The timestamp of the last request received, to millisecond
              precision if available on the server."
           ::= { serverClientEntry 4 }
     
        serverClientLastRequestType  OBJECT-TYPE
           SYNTAX      INTEGER {
              bootprequest(0)
              dhcpdiscover(1),
              dhcprequest(3),
              dhcpdecline(4),
              dhcprelease(7),
              dhcpinform(8)
              dhcpleasequery(TBD),-- /*new*/
           }
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The type of the last request message received for this
              client.If the server does not capture this information, the
              value 32,767 is returned."
           REFERENCE
              "RFC2131; RFC2132, section 9.6; draft-ietf-dhc-leasequery-
              02.txt."
           ::= { serverClientEntry 5 }
     
        serverClientLastResponseType  OBJECT-TYPE
           SYNTAX      INTEGER {
     
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              bootpreply(1),
              dhcpoffer(2),
              dhcpack(5),
              dhcpnak(6)
              dhcpknown(TBD),-- /*new*/
              dhcpunknown(TBD)-- /*new*/
           }
           MAX-ACCESS  read-only
           STATUS      current
           DESCRIPTION
              "The type of the last response message sent to this client.  If
              the server does not capture this information, the value 32,767
              is returned."
           REFERENCE
              "RFC2131; RFC2132, section 9.6;draft-ietf-dhc-pv4-reconfigure-
              06.txt;draft-ietf-dhc-leasequery-02.txt"
           ::= { serverClientEntry 6 }
     
     
        --serverNotifyObjects: Objects which are used only in notifications
     
        serverNotifyDuplicateIPAddress  OBJECT-TYPE
           SYNTAX      IpAddress
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The IP address found to be a duplicate.  Duplicates are
              detected by servers which issue an ICMP ECHOREQUEST prior to
              offering an IP address lease."
           ::= { serverNotifyObjects 1 }
     
        serverNotifyDuplicateMAC  OBJECT-TYPE
           SYNTAX      PhysicalAddress
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The offending MAC address which caused a duplicate IP address
              to be detected, if captured by the server, else 00-00-00-00-00-
              00."
           ::= { serverNotifyObjects 2 }
     
        serverNotifyClientDuplicateIP  OBJECT-TYPE-- /*renamed*/
           SYNTAX      IpAddress
           MAX-ACCESS  accessible-for-notify
           STATUS      current
           DESCRIPTION
              "The IP Address offered by a server that the requesting client
              has determined to be a duplicate, detected by means of a
              gratuitous ARP message and reported through a DHCPDECLINE
              message."
     
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           ::= { serverNotifyObjects 3 }
     
     
        -- Notifications
     
        serverMIBNotificationPrefix  OBJECT IDENTIFIER
        ::= { serverMIB 2 }serverMIBNotifications OBJECT IDENTIFIER
        ::= { serverMIBNotificationPrefix 0 }
     
        serverFreeAddressLow  NOTIFICATION-TYPE
           OBJECTS {
              serverSharedNetworkFreeAddressLowThreshold,
              serverSharedNetworkFreeAddresses
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that the number of available IP
              addresses for a particular shared network has fallen below the
              value of serverSharedNetworkFreeAddressLowThreshold for that
              shared network."
        ::= { serverMIBNotifications 1 }
     
        serverFreeAddressHigh  NOTIFICATION-TYPE
           OBJECTS {
              serverSharedNetworkFreeAddressHighThreshold,
              serverSharedNetworkFreeAddresses
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that the number of available IP
              addresses for a particular shared network has risen above the
              value of serverSharedNetworkFreeAddressHighThreshold for that
              shared network."
        ::= { serverMIBNotifications 2 }
     
        serverServerStart  NOTIFICATION-TYPE
           OBJECTS     { serverNotifyClientDuplicateIP }
           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."
        ::= { serverMIBNotifications 3 }
     
        serverServerStop  NOTIFICATION-TYPE
           OBJECTS  { serverNotifyClientDuplicateIP }
           STATUS         current
           DESCRIPTION
     
     
     
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              "This notification signifies that the server of the specified
              type has stopped normally on the host from which this
              notification has been sent."
        ::= { serverMIBNotifications 4 }
     
        serverDuplicateAddress NOTIFICATION-TYPE
           OBJECTS {
              serverNotifyDuplicateIPAddress,
              serverNotifyDuplicateMAC,
              serverNotifyClientDuplicateMAC
           }
           STATUS      current
           DESCRIPTION
              "This notification signifies that a duplicate IP 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
              IP address as unavailable for leasing to clients.  The
              serverNotifyClientDuplicateMAC object indicates whether the
              client or server detected this condition."
        ::= { serverMIBNotifications 5 }-- /*renumbered*/
     
        serverAddressConflict NOTIFICATION-TYPE
           OBJECTS     { serverNotifyClientDuplicateIP }
           STATUS      current
           DESCRIPTION
        ::= { serverMIBNotifications 6 }-- /*renumbered*/
     
     
     
        -- Conformance
     
        serverMIBConformanceOBJECT-IDENTITY
           STATUS      current
           DESCRIPTION
              "DHCP Server MIB objects are all defined in this branch."
        ::= { serverMIB 3 }
     
        serverMIBCompliancesOBJECT IDENTIFIER
        ::= { serverMIBConformance 1 }
     
        serverMIBGroupsOBJECT IDENTIFIER
        ::= { serverMIBConformance 2 }
     
     
        -- Compliance groups
     
        serverMIBCompliance MODULE-COMPLIANCE
     
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           MODULE-- this module
           MANDATORY-GROUPS {
              serverSystemGroup,
              bootpCountersGroup,
              dhcpCountersGroup,
              serverConfigurationGroup,
              serverClientsGroup
           }
           OPTIONAL-GROUPS {
              bootpOptionalStatisticsGroup,
              dhcpOptionalStatisticsGroup
           }
           STATUS      current
           DESCRIPTION
              "Describes the requirements for conformance to the DCHP Server
              MIB"
        ::= { serverMIBCompliances 1 }
     
     
        -- Object groups
     
        serverSystemGroup OBJECT-GROUP
           OBJECTS {
              serverSystemDescr,
              serverSystemObjectID
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the serverSystemGroup."
        ::= { serverMIBGroups 1 }
     
        bootpCountersGroup OBJECT-GROUP
           OBJECTS {
              bootpCountRequests,
              bootpCountInvalids,
              bootpCountReplies,
              bootpCountDroppedUnknownClients,
              bootpCountDroppedNotServingSubnet
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the bootpBountersGroup."
        ::= { serverMIBGroups 2 }
     
        dhcpCountersGroup OBJECT-GROUP
           OBJECTS {
              dhcpCountDiscovers,
              dhcpCountRequests,
              dhcpCountReleases,
              dhcpCountDeclines,
     
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              dhcpCountInforms,
              dhcpCountInvalids,
              dhcpCountOffers,
              dhcpCountAcks,
              dhcpCountNacks,
              dhcpCountDroppedUnknownClient,
              dhcpCountDroppedNotServingSubnet
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpCountersGroup."
        ::= { serverMIBGroups 3 }
     
        bootpOptionalStatisticsGroup OBJECT-GROUP
           OBJECTS {
              bootpStatMinArrivalInterval,
              bootpStatMaxArrivalInterval,
              bootpStatLastArrivalTime,
              bootpStatSumSquaresArrivalTime,
              bootpStatMinResponseTime,
              bootpStatMaxResponseTime,
              bootpStatSumReponseTime,
              bootpStatSumSquaresResponseTime
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the bootpOptionalStatisticsGroup."
        ::= { serverMIBGroups 4 }
     
        dhcpOptionalStatisticsGroup OBJECT-GROUP
           OBJECTS {
              dhcpStatMinArrivalInterval,
              dhcpStatMaxArrivalInterval,
              dhcpStatLastArrivalTime,
              dhcpStatSumSquaresArrivalTime,
              dhcpStatMinResponseTime,
              dhcpStatMaxResponseTime,
              dhcpStatSumResponseTime,
              dhcpStatSumSquaresResponseTime
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the dhcpOptionalStatisticsGroup."
        ::= { serverMIBGroups 5 }
     
        serverConfigurationGroup OBJECT-GROUP
           OBJECTS {
              serverSubnet,
              serverSubnetMask,
              serverSubnetSharedNetwork,
     
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              serverRangeStart,
              serverRangeEnd,
              serverRangeSubnetMask,
              serverRangeInUse,
              serverRangeOutstandingOffers,
              serverAddress,
              serverAddressSubnetMask,
              serverAddressRange,
              serverAddressType,
              serverAddressTimeRemaining,
              serverAddressAllowedProtocol,
              serverAddressServedProtocol,
              serverAddressHardwareAddress,
              serverAddressClientId,
              serverAddressHostName,
              serverAddressDomainName
              }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the serverConfigurationGroup."
        ::= { serverMIBGroups 6 }
     
        serverClientsGroup OBJECT-GROUP
           OBJECTS {
              serverClientHardwareAddress,
              serverClientSubnetMask,
              serverClientAddress,
              serverClientLastRequestTime,
              serverClientLastRequestType,
              serverClientLastResponseType
           }
           STATUS      current
           DESCRIPTION
              "Objects belonging to the serverClientsGroup."
        ::= { serverMIBGroups 7 }
     
        serverSharedNetworkObjectsGroup OBJECT-GROUP
           OBJECTS {
              serverSharedNetworkFreeAddressLowThreshold,
              serverSharedNetworkFreeAddressHighThreshold,
              serverSharedNetworkFreeAddressValue
           }
           STATUS      current
           DESCRIPTION
              "DHCP Server MIB objects used in shared networks."
        ::= { serverMIBGroups 8 }
     
        serverNotifyObjectsGroup OBJECT-GROUP
           OBJECTS {
              serverNotifyDuplicateIPAddress,
     
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              serverNotifyDuplicateMAC,
              serverNotifyClientDuplicateMAC,
              serverNotifyClientDuplicateIP,
              serverNotifyContestedIpAddress
           }
           STATUS      current
           DESCRIPTION
              "DHCP Server MIB objects used in notifications."
        ::= { serverMIBGroups 9 }
     
        serverNotificationsGroup NOTIFICATION-GROUP
           NOTIFICATIONS {
              serverFreeAddressLow,
              serverFreeAddressHigh,
              serverServerStart,
              serverServerStop,
              serverDNSQueueTooBig,
              serverOtherServerNotResponding,
              serverDuplicateAddress,
              serverAddressConflict,
              serverOtherServerResponding,
              serverFailoverConfigMismatch
           }
           STATUS      current
           DESCRIPTION
              "Notifications that are implemented by the DHCP Server agent."
        ::= { serverMIBGroups 10 }
     
        END
     
     
     
     4. 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.
     
     
     
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        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.
     
     
     5. Notes
     
        This section will be removed when this memo goes to Working Group
        Last Call.
     
     
     5.1. Issues
     
        Not all of these issues have been resolved, even in the latest (-07)
        draft.  Some may become items for future study, while some will
        probably be dropped.
     
        o  Are placeholders for expected DHCP option values a good or bad
           idea?
     
        o  Ryan Troll proposed four or five traps that Nathan Lane
           enthusiastically supported, but it has been difficult to achieve
           any consensus (or, for that matter, much interest) in them.
     
        o  What is the best way to reset counters and statistics?  Is it
           necessary to reset them at all?  The -07 draft does not declare
           any counters as read-write or read-create, primarily to avoid
           these questions, as well as to provide fundamental security over
           objects.
     
           -- Do we need to reset them individually, as groups, or as a
              whole?
     
           -- Do we need a timestamp of when they were reset?
     
        o  Should all invalid packets received be collapsed into a single
           counter for each protocol type (BOOTP and DHCP), or broken out by
           type of error?
     
        o  If counted by error type, what is the set of errors that we should
           use?
     
        o  Perhaps we should develop a common vocabulary (and glossary) for
           terms such as "abandoned" so that the objects defined and their
           descriptions aren't misinterpreted by implementers.
     
        o  Do we need to be concerned about the potential size of some of the
           configuration data tables?  Wouldn't it be better to maintain
     
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           counters for things like number of leases assigned than to expect
           the management station to calculate the values by reading very
           large tables to count the number of leases in that state?
     
     
     5.2. Changes from Prior Drafts
     
        The "-01" revision removed the Server Identity section from the
        proposed MIB, relying on the Application MIB to accomplish the same
        result.
     
        The min/max (inter-arrival and response times) were changed to
        Unsigned32 so that they could be reset.  Sums of inter-arrival and
        response times were deleted since the management station can easily
        calculate them.  The last arrival time objects were added.
     
        The "-03" version incorporated the proposed configuration tables
        suggested by Ryan Troll of CMU.  The "01" revision of this version
        added three elements to the server subnet table, number of
        outstanding offers, number of addresses in use, and number of free
        addresses, as well as changing subnet address to subnet mask in the
        server address, server range, and client address tables.  The client
        MAC address element of the client address table was separated into a
        1-octet hardware type and a 16-octet client hardware address, causing
        a renumbering of the elements in this table.  Clarifying text was
        added to several element descriptions, and limitations on values, and
        the reported value when the server did not support the data element
        were also specified.  This version also incorporated an address
        change for one of the authors, revisions to standard text required by
        the IETF, and some editorial clarifications.
     
        The "-04" version changed the maximum size of the object
        serverAddressHostName from 64 to 255 octets, and added clarifying
        text to both that object and to serverAddressDomainName regarding the
        practical values for the length of both objects.
     
        The "-05" version added a number of traps suggested by Kim Kinnear,
        made a number of small renaming and renumbering changes (annotated in
        the MIB itself) and added the Shared Network concept to describe
        shared network segments: several subnetworks that coexist on one
        medium.  This was done partly because the Address Range concept did
        not adequately describe the "scoping" of address pools as is common
        with many current server implementations.  Also updated the authorÆs
        address and contact information, and incorporated a number of
        corrections and amplifications suggested by various readers of the "-
        04" draft, including a missing OID for serverNotifyObjects and a
        syntax error for PhysicalAddress.
     
        The "-06" version corrects a number of flaws reported by Rick Geesen
        and Jin Tao, mostly caused by typographical errors in the "-05"
     
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        version as well as some unintentionally omitted text for
        serverNotifyObjects.
     
        The "-07" version changes BOOTP and DHCP statistics from mandatory to
        optional, renaming object identifiers as required to match.  All
        objects, tables, and groups in previous drafts for Dynamic DNS
        updating and Failover have been removed.  All tables were carefully
        examined to be certain that they really could be simply implemented.
        Many items were renamed or renumbered.  Placeholder definitions of
        message types (both requests and responses) were added to support
        DHCPFORCERENEW, DHCPQUERY, DHCPKNOWN, and DHCPUNKNOWN.  A few [more]
        typographical errors were found and fixed.  Because of an error
        posting the û07 draft to the editor's queue it was not accepted in
        time for IETF-52 and is being submitted to the Internet-Drafts editor
        with one change identified by Alan Hackert.  Finally, some of the
        initial text was brought in line with standard requirements for
        Internet-Drafts.
     
     
     6. Acknowledgements
     
        This document is the result of work undertaken the by 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 development of this MIB.
     
        Thanks to Ryan Troll, Nathan Lane, Kim Kinnear, Yannick Koehler,
        Nathan Lane, Rick Geesen, Jin Tao, James Brister, and Alan Hackert
        for their review, comments, and contributions.
     
     
     7. 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.  Many
        network administrators object to settable management objects because
        of the limited security features of SNMPv1 and SNMPv2.  We have
        chosen not to fight that battle in constructing this MIB.
     
        SNMPv1 by itself is not a secure environment.  Even if the network
        itself is secure (for example by using IPSEC), there is no control as
        to who on the secure network is allowed to access and GET / SET (read
        / change / create / delete) the objects in this MIB.
     
     
     
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        SNMPv2 communities provide a minimal level of access control, but it
        is recommended that the implementers consider the security features
        as provided by the SNMPv3 framework.  Specifically, the use of the
        User-based Security Model [RFC2274] and the View-based Access Control
        Model [RFC2275] is recommended.
     
        It is then a customer/user responsibility to ensure that the SNMP
        entity giving access to an instance of this MIB, 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.
     
     
     8. References
     
       [DEN] Directory Enabled Networks Working Group,
          http://www.universe.digex.net/~murchiso/den.
     
       [RFC1123] R. Braden, "Requirements for Internet Hosts -- Application
          and Support," RFC 1123, October 1989.
     
       [RFC2287] Krupczak, R., and J. Saperia, "Definitions of System-Level
          Managed Objects for Applications," RFC 2287, February 1998.
     
       [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.
     
       [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
          Requirement Levels," RFC 2119, BCP 14, March 1997.
     
       [RFC2131] Droms, R., "Dynamic Host Configuration Protocol," RFC 2131,
          March 1997.
     
     
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     Internet Draft             DHCP Server MIB             February 2002
     
       [RFC2132] Alexander, S. and Droms, R., "DHCP Options and BOOTP Vendor
          Extensions," RFC 2132, March 1997.
     
       [RFC2287] Krupczak, C. and Saperia, J., "Definitions of System-Level
          Managed Objects for Applications," RFC 2287, February 1998.
     
       <draft-ietf-dhc-pv4-reconfigure-06.txt>, Yves T'Joens and Christian
          Hublet, Peter De Schrijver, "The DHCP Reconfigure Extension," July
          2001
     
       <draft-ietf-dhc-leasequery-02.txt>, Rich Woundy and Kim Kinnear,
          "DHCP Lease Query," July 2001
     
     
     9. 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
     
     
     10. Full Copyright Statement
     
        Copyright (C) The Internet Society, 2002.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
     
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        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
        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.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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