Network Working Group                                         R. Austein
Request for Comments: 1612               Epilogue Technology Corporation
Category: Standards Track                                     J. Saperia
                                           Digital Equipment Corporation
                                                                May 1994


                      DNS Resolver MIB Extensions

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Table of Contents

   1. Introduction ..............................................    1
   2. The SNMPv2 Network Management Framework ...................    2
   2.1 Object Definitions .......................................    2
   3. Overview ..................................................    2
   3.1 Resolvers ................................................    3
   3.2 Name Servers .............................................    3
   3.3 Selected Objects .........................................    4
   3.4 Textual Conventions ......................................    4
   4. Definitions ...............................................    5
   5. Acknowledgements ..........................................   30
   6. References ................................................   30
   7. Security Considerations ...................................   32
   8. Authors' Addresses ........................................   32

1.  Introduction

   This memo 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 which instrument DNS
   resolver functions.  This memo was produced by the DNS working group.

   With the adoption of the Internet-standard Network Management
   Framework [4,5,6,7], and with a large number of vendor
   implementations of these standards in commercially available
   products, it became possible to provide a higher level of effective
   network management in TCP/IP-based internets than was previously
   available.  With the growth in the use of these standards, it has
   become possible to consider the management of other elements of the
   infrastructure beyond the basic TCP/IP protocols.  A key element of

   the TCP/IP infrastructure is the DNS.

   Up to this point there has been no mechanism to integrate the
   management of the DNS with SNMP-based managers.  This memo provides
   the mechanisms by which IP-based management stations can effectively
   manage DNS resolver software in an integrated fashion.

   We have defined DNS MIB objects to be used in conjunction with the
   Internet MIB to allow access to and control of DNS resolver software
   via SNMP by the Internet community.

2.  The SNMPv2 Network Management Framework

   The SNMPv2 Network Management Framework consists of four major
   components.  They are:

      o  RFC 1442 which defines the SMI, the mechanisms used for
         describing and naming objects for the purpose of management.

      o  STD 17, RFC 1213 defines MIB-II, the core set of managed
         objects for the Internet suite of protocols.

      o  RFC 1445 which defines the administrative and other
         architectural aspects of the framework.

      o  RFC 1448 which defines the protocol used for network access to
         managed objects.

   The Framework permits new objects to be defined for the purpose of
   experimentation and evaluation.

2.1.  Object Definitions

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1)
   defined in the SMI.  In particular, each object object type is named
   by an OBJECT IDENTIFIER, an administratively assigned name.  The
   object type together with an object instance serves to uniquely
   identify a specific instantiation of the object.  For human
   convenience, we often use a textual string, termed the descriptor, to
   refer to the object type.

3.  Overview

   In theory, the DNS world is pretty simple.  There are two kinds of
   entities: resolvers and name servers.  Resolvers ask questions.  Name
   servers answer them.  The real world, however, is not so simple.

   Implementors have made widely differing choices about how to divide
   DNS functions between resolvers and servers.  They have also
   constructed various sorts of exotic hybrids.  The most difficult task
   in defining this MIB was to accommodate this wide range of entities
   without having to come up with a separate MIB for each.

   We divided up the various DNS functions into two, non-overlapping
   classes, called "resolver functions" and "name server functions."  A
   DNS entity that performs what we define as resolver functions
   contains a resolver, and therefore must implement the MIB groups
   required of all resolvers which are defined in this module.  Some
   resolvers also implement "optional" functions such as a cache, in
   which case they must also implement the cache group contained in this
   MIB.  A DNS entity which implements name server functions is
   considered to be a name server, and must implement the MIB groups
   required for name servers which are defined in a separate module.  If
   the same piece of software performs both resolver and server
   functions, we imagine that it contains both a resolver and a server
   and would thus implement both the DNS Server and DNS Resolver MIBs.

3.1.  Resolvers

   In our model, a resolver is a program (or piece thereof) which
   obtains resource records from servers.  Normally it does so at the
   behest of an application, but may also do so as part of its own
   operation.  A resolver sends DNS protocol queries and receives DNS
   protocol replies.  A resolver neither receives queries nor sends
   replies.  A full service resolver is one that knows how to resolve
   queries: it obtains the needed resource records by contacting a
   server authoritative for the records desired.  A stub resolver does
   not know how to resolve queries: it sends all queries to a local name
   server, setting the "recursion desired" flag to indicate that it
   hopes that the name server will be willing to resolve the query.  A
   resolver may (optionally) have a cache for remembering previously
   acquired resource records.  It may also have a negative cache for
   remembering names or data that have been determined not to exist.

3.2.  Name Servers

   A name server is a program (or piece thereof) that provides resource
   records to resolvers.  All references in this document to "a name
   server" imply "the name server's role"; in some cases the name
   server's role and the resolver's role might be combined into a single
   program.  A name server receives DNS protocol queries and sends DNS
   protocol replies.  A name server neither sends queries nor receives
   replies.  As a consequence, name servers do not have caches.
   Normally, a name server would expect to receive only those queries to
   which it could respond with authoritative information.  However, if a

   name server receives a query that it cannot respond to with purely
   authoritative information, it may choose to try to obtain the
   necessary additional information from a resolver which may or may not
   be a separate process.

3.3.  Selected Objects

   Many of the objects included in this memo have been created from
   information contained in the DNS specifications [1,2], as amended and
   clarified by subsequent host requirements documents [3].  Other
   objects have been created based on experience with existing DNS
   management tools, expected operational needs, the statistics
   generated by existing DNS implementations, and the configuration
   files used by existing DNS implementations.  These objects have been
   ordered into groups as follows:

         o  Resolver Configuration Group

         o  Resolver Counter Group

         o  Resolver Lame Delegation Group

         o  Resolver Cache Group

         o  Resolver Negative Cache Group

         o  Resolver Optional Counter Group

   This information has been converted into a standard form using the
   SNMPv2 SMI defined in [9].  For the most part, the descriptions are
   influenced by the DNS related RFCs noted above.  For example, the
   descriptions for counters used for the various types of queries of
   DNS records are influenced by the definitions used for the various
   record types found in [2].

3.4.  Textual Conventions

   Several conceptual data types have been introduced as a textual
   conventions in the DNS Server MIB document and have been imported
   into this MIB module.  These additions will facilitate the common
   understanding of information used by the DNS.  No changes to the SMI
   or the SNMP are necessary to support these conventions.

   Readers familiar with MIBs designed to manage entities in the lower
   layers of the Internet protocol suite may be surprised at the number
   of non-enumerated integers used in this MIB to represent values such
   as DNS RR class and type numbers.  The reason for this choice is
   simple: the DNS itself is designed as an extensible protocol,

   allowing new classes and types of resource records to be added to the
   protocol without recoding the core DNS software.  Using non-
   enumerated integers to represent these data types in this MIB allows
   the MIB to accommodate these changes as well.

4.  Definitions

   DNS-RESOLVER-MIB DEFINITIONS ::= BEGIN

   IMPORTS
       MODULE-IDENTITY, OBJECT-TYPE, IpAddress, Counter32, Integer32
           FROM SNMPv2-SMI
       TEXTUAL-CONVENTION, RowStatus, DisplayString
           FROM SNMPv2-TC
       MODULE-COMPLIANCE, OBJECT-GROUP
           FROM SNMPv2-CONF
       dns, DnsName, DnsNameAsIndex, DnsClass, DnsType, DnsQClass,
       DnsQType, DnsTime, DnsOpCode, DnsRespCode
           FROM DNS-SERVER-MIB;

   -- DNS Resolver MIB

   dnsResMIB MODULE-IDENTITY
       LAST-UPDATED "9401282250Z"
       ORGANIZATION "IETF DNS Working Group"
       CONTACT-INFO
               "       Rob Austein
               Postal: Epilogue Technology Corporation
                       268 Main Street, Suite 283
                       North Reading, MA 10864
                       US
                  Tel: +1 617 245 0804
                  Fax: +1 617 245 8122
               E-Mail: sra@epilogue.com

                       Jon Saperia
               Postal: Digital Equipment Corporation
                       110 Spit Brook Road
                       ZKO1-3/H18
                       Nashua, NH 03062-2698
                       US
                  Tel: +1 603 881 0480
                  Fax: +1 603 881 0120
               E-mail: saperia@zko.dec.com"
       DESCRIPTION
               "The MIB module for entities implementing the client
               (resolver) side of the Domain Name System (DNS)
               protocol."

       ::= { dns 2 }

   dnsResMIBObjects        OBJECT IDENTIFIER ::= { dnsResMIB 1 }

   -- (Old-style) groups in the DNS resolver MIB.

   dnsResConfig            OBJECT IDENTIFIER ::= { dnsResMIBObjects 1 }
   dnsResCounter           OBJECT IDENTIFIER ::= { dnsResMIBObjects 2 }
   dnsResLameDelegation    OBJECT IDENTIFIER ::= { dnsResMIBObjects 3 }
   dnsResCache             OBJECT IDENTIFIER ::= { dnsResMIBObjects 4 }
   dnsResNCache            OBJECT IDENTIFIER ::= { dnsResMIBObjects 5 }
   dnsResOptCounter        OBJECT IDENTIFIER ::= { dnsResMIBObjects 6 }


   -- Resolver Configuration Group

   dnsResConfigImplementIdent OBJECT-TYPE
       SYNTAX      DisplayString
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "The implementation identification string for the
               resolver software in use on the system, for example;
               `RES-2.1'"
       ::= { dnsResConfig 1 }

   dnsResConfigService OBJECT-TYPE
       SYNTAX      INTEGER { recursiveOnly(1),
                             iterativeOnly(2),
                             recursiveAndIterative(3) }
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Kind of DNS resolution service provided:

               recursiveOnly(1) indicates a stub resolver.

               iterativeOnly(2) indicates a normal full service
               resolver.

               recursiveAndIterative(3) indicates a full-service
               resolver which performs a mix of recursive and iterative
               queries."
        ::= { dnsResConfig 2 }

   dnsResConfigMaxCnames OBJECT-TYPE
       SYNTAX      INTEGER (0..2147483647)
       MAX-ACCESS  read-write

       STATUS      current
       DESCRIPTION
               "Limit on how many CNAMEs the resolver should allow
               before deciding that there's a CNAME loop.  Zero means
               that resolver has no explicit CNAME limit."
       REFERENCE
               "RFC-1035 section 7.1."
       ::= { dnsResConfig 3 }

   -- DNS Resolver Safety Belt Table

   dnsResConfigSbeltTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResConfigSbeltEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Table of safety belt information used by the resolver
               when it hasn't got any better idea of where to send a
               query, such as when the resolver is booting or is a stub
               resolver."
       ::= { dnsResConfig 4 }

   dnsResConfigSbeltEntry OBJECT-TYPE
       SYNTAX      DnsResConfigSbeltEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "An entry in the resolver's Sbelt table.
               Rows may be created or deleted at any time by the DNS
               resolver and by SNMP SET requests.  Whether the values
               changed via SNMP are saved in stable storage across
               `reset' operations is implementation-specific."
       INDEX     { dnsResConfigSbeltAddr,
                   dnsResConfigSbeltSubTree,
                   dnsResConfigSbeltClass }
       ::= { dnsResConfigSbeltTable 1 }

   DnsResConfigSbeltEntry ::=
       SEQUENCE {
           dnsResConfigSbeltAddr
               IpAddress,
           dnsResConfigSbeltName
               DnsName,
           dnsResConfigSbeltRecursion
               INTEGER,
           dnsResConfigSbeltPref
               INTEGER,
           dnsResConfigSbeltSubTree

               DnsNameAsIndex,
           dnsResConfigSbeltClass
               DnsClass,
           dnsResConfigSbeltStatus
               RowStatus
       }

   dnsResConfigSbeltAddr OBJECT-TYPE
       SYNTAX      IpAddress
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "The IP address of the Sbelt name server identified by
               this row of the table."
       ::= { dnsResConfigSbeltEntry 1 }

   dnsResConfigSbeltName OBJECT-TYPE
       SYNTAX      DnsName
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
               "The DNS name of a Sbelt nameserver identified by this
               row of the table.  A zero-length string indicates that
               the name is not known by the resolver."
       ::= { dnsResConfigSbeltEntry 2 }

   dnsResConfigSbeltRecursion OBJECT-TYPE
       SYNTAX      INTEGER { iterative(1),
                             recursive(2),
                             recursiveAndIterative(3) }
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
               "Kind of queries resolver will be sending to the name
               server identified in this row of the table:

               iterative(1) indicates that resolver will be directing
               iterative queries to this name server (RD bit turned
               off).

               recursive(2) indicates that resolver will be directing
               recursive queries to this name server (RD bit turned
               on).

               recursiveAndIterative(3) indicates that the resolver
               will be directing both recursive and iterative queries
               to the server identified in this row of the table."
        ::= { dnsResConfigSbeltEntry 3 }

   dnsResConfigSbeltPref OBJECT-TYPE
       SYNTAX      INTEGER (0..2147483647)
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
               "This value identifies the preference for the name server
               identified in this row of the table.  The lower the
               value, the more desirable the resolver considers this
               server."
        ::= { dnsResConfigSbeltEntry 4 }

   dnsResConfigSbeltSubTree OBJECT-TYPE
       SYNTAX      DnsNameAsIndex
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Queries sent to the name server identified by this row
               of the table are limited to those for names in the name
               subtree identified by this variable.  If no such
               limitation applies, the value of this variable is the
               name of the root domain (a DNS name consisting of a
               single zero octet)."
       ::= { dnsResConfigSbeltEntry 5 }

   dnsResConfigSbeltClass OBJECT-TYPE
       SYNTAX      DnsClass
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "The class of DNS queries that will be sent to the server
               identified by this row of the table."
       ::= { dnsResConfigSbeltEntry 6 }

   dnsResConfigSbeltStatus OBJECT-TYPE
       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
               "Row status column for this row of the Sbelt table."
       ::= { dnsResConfigSbeltEntry 7 }

   dnsResConfigUpTime OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "If the resolver has a persistent state (e.g., a
               process), this value will be the time elapsed since it

               started.  For software without persistant state, this
               value will be 0."
       ::= { dnsResConfig 5 }

   dnsResConfigResetTime OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "If the resolver has a persistent state (e.g., a process)
               and supports a `reset' operation (e.g., can be told to
               re-read configuration files), this value will be the
               time elapsed since the last time the resolver was
               `reset.'  For software that does not have persistence or
               does not support a `reset' operation, this value will be
               zero."
       ::= { dnsResConfig 6 }

   dnsResConfigReset OBJECT-TYPE
       SYNTAX      INTEGER { other(1),
                             reset(2),
                             initializing(3),
                             running(4) }
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status/action object to reinitialize any persistant
               resolver state.  When set to reset(2), any persistant
               resolver state (such as a process) is reinitialized as if
               the resolver had just been started.  This value will
               never be returned by a read operation.  When read, one of
               the following values will be returned:
                   other(1) - resolver in some unknown state;
                   initializing(3) - resolver (re)initializing;
                   running(4) - resolver currently running."
       ::= { dnsResConfig 7 }


   -- Resolver Counters Group

   -- Resolver Counter Table

   dnsResCounterByOpcodeTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResCounterByOpcodeEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Table of the current count of resolver queries and

               answers."
       ::= { dnsResCounter 3 }

   dnsResCounterByOpcodeEntry OBJECT-TYPE
       SYNTAX      DnsResCounterByOpcodeEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Entry in the resolver counter table.  Entries are
               indexed by DNS OpCode."
       INDEX     { dnsResCounterByOpcodeCode }
       ::= { dnsResCounterByOpcodeTable 1 }

   DnsResCounterByOpcodeEntry ::=
       SEQUENCE {
           dnsResCounterByOpcodeCode
               DnsOpCode,
           dnsResCounterByOpcodeQueries
               Counter32,
           dnsResCounterByOpcodeResponses
               Counter32
       }

   dnsResCounterByOpcodeCode OBJECT-TYPE
       SYNTAX      DnsOpCode
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "The index to this table.  The OpCodes that have already
               been defined are found in RFC-1035."
       REFERENCE
               "RFC-1035 section 4.1.1."
       ::= { dnsResCounterByOpcodeEntry 1 }

   dnsResCounterByOpcodeQueries OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Total number of queries that have sent out by the
               resolver since initialization for the OpCode which is
               the index to this row of the table."
       ::= { dnsResCounterByOpcodeEntry 2 }

   dnsResCounterByOpcodeResponses OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current

       DESCRIPTION
               "Total number of responses that have been received by the
               resolver since initialization for the OpCode which is
               the index to this row of the table."
       ::= { dnsResCounterByOpcodeEntry 3 }

   -- Resolver Response Code Counter Table

   dnsResCounterByRcodeTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResCounterByRcodeEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Table of the current count of responses to resolver
               queries."
       ::= { dnsResCounter 4 }

   dnsResCounterByRcodeEntry OBJECT-TYPE
       SYNTAX      DnsResCounterByRcodeEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Entry in the resolver response table.  Entries are
               indexed by DNS response code."
       INDEX     { dnsResCounterByRcodeCode }
       ::= { dnsResCounterByRcodeTable 1 }

   DnsResCounterByRcodeEntry ::=
       SEQUENCE {
           dnsResCounterByRcodeCode
               DnsRespCode,
           dnsResCounterByRcodeResponses
               Counter32
       }

   dnsResCounterByRcodeCode OBJECT-TYPE
       SYNTAX      DnsRespCode
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "The index to this table.  The Response Codes that have
               already been defined are found in RFC-1035."
       REFERENCE
               "RFC-1035 section 4.1.1."
       ::= { dnsResCounterByRcodeEntry 1 }

   dnsResCounterByRcodeResponses OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of responses the resolver has received for the
               response code value which identifies this row of the
               table."
       ::= { dnsResCounterByRcodeEntry 2 }

   -- Additional DNS Resolver Counter Objects

   dnsResCounterNonAuthDataResps OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of requests made by the resolver for which a
               non-authoritative answer (cached data) was received."
       ::= { dnsResCounter 5 }

   dnsResCounterNonAuthNoDataResps OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of requests made by the resolver for which a
               non-authoritative answer - no such data response (empty
               answer) was received."
       ::= { dnsResCounter 6 }

   dnsResCounterMartians OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of responses received which were received from
               servers that the resolver does not think it asked."
       ::= { dnsResCounter 7 }

   dnsResCounterRecdResponses OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of responses received to all queries."
       ::= { dnsResCounter 8 }

   dnsResCounterUnparseResps OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of responses received which were unparseable."
       ::= { dnsResCounter 9 }

   dnsResCounterFallbacks OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of times the resolver had to fall back to its
               seat belt information."
       ::= { dnsResCounter 10 }


   -- Lame Delegation Group

   dnsResLameDelegationOverflows OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of times the resolver attempted to add an entry
               to the Lame Delegation table but was unable to for some
               reason such as space constraints."
       ::= { dnsResLameDelegation 1 }

   -- Lame Delegation Table

   dnsResLameDelegationTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResLameDelegationEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Table of name servers returning lame delegations.

               A lame delegation has occured when a parent zone
               delegates authority for a child zone to a server that
               appears not to think that it is authoritative for the
               child zone in question."
       ::= { dnsResLameDelegation 2 }

   dnsResLameDelegationEntry OBJECT-TYPE
       SYNTAX      DnsResLameDelegationEntry
       MAX-ACCESS  not-accessible

       STATUS      current
       DESCRIPTION
               "Entry in lame delegation table.  Only the resolver may
               create rows in this table.  SNMP SET requests may be used
               to delete rows."
       INDEX     { dnsResLameDelegationSource,
                   dnsResLameDelegationName,
                   dnsResLameDelegationClass }
       ::= { dnsResLameDelegationTable 1 }

   DnsResLameDelegationEntry ::=
       SEQUENCE {
           dnsResLameDelegationSource
               IpAddress,
           dnsResLameDelegationName
               DnsNameAsIndex,
           dnsResLameDelegationClass
               DnsClass,
           dnsResLameDelegationCounts
               Counter32,
           dnsResLameDelegationStatus
               RowStatus
       }

   dnsResLameDelegationSource OBJECT-TYPE
       SYNTAX      IpAddress
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Source of lame delegation."
       ::= { dnsResLameDelegationEntry 1 }

   dnsResLameDelegationName OBJECT-TYPE
       SYNTAX      DnsNameAsIndex
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS name for which lame delegation was received."
       ::= { dnsResLameDelegationEntry 2 }

   dnsResLameDelegationClass OBJECT-TYPE
       SYNTAX      DnsClass
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS class of received lame delegation."
       ::= { dnsResLameDelegationEntry 3 }

   dnsResLameDelegationCounts OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "How many times this lame delegation has been received."
       ::= { dnsResLameDelegationEntry 4 }

   dnsResLameDelegationStatus OBJECT-TYPE
       SYNTAX      RowStatus
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status column for the lame delegation table.  Since only
               the agent (DNS resolver) creates rows in this table, the
               only values that a manager may write to this variable
               are active(1) and destroy(6)."
       ::= { dnsResLameDelegationEntry 5 }


   -- Resolver Cache Group

   dnsResCacheStatus OBJECT-TYPE
       SYNTAX      INTEGER { enabled(1), disabled(2), clear(3) }
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status/action for the resolver's cache.

               enabled(1) means that the use of the cache is allowed.
               Query operations can return this state.

               disabled(2) means that the cache is not being used.
               Query operations can return this state.

               Setting this variable to clear(3) deletes the entire
               contents of the resolver's cache, but does not otherwise
               change the resolver's state.  The status will retain its
               previous value from before the clear operation (i.e.,
               enabled(1) or disabled(2)).  The value of clear(3) can
               NOT be returned by a query operation."
       ::= { dnsResCache 1 }

   dnsResCacheMaxTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION

               "Maximum Time-To-Live for RRs in this cache.  If the
               resolver does not implement a TTL ceiling, the value of
               this field should be zero."
       ::= { dnsResCache 2 }

   dnsResCacheGoodCaches OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of RRs the resolver has cached successfully."
       ::= { dnsResCache 3 }

   dnsResCacheBadCaches OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of RRs the resolver has refused to cache because
               they appear to be dangerous or irrelevant.  E.g., RRs
               with suspiciously high TTLs, unsolicited root
               information, or that just don't appear to be relevant to
               the question the resolver asked."
       ::= { dnsResCache 4 }

   -- Resolver Cache Table

   dnsResCacheRRTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResCacheRREntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "This table contains information about all the resource
               records currently in the resolver's cache."
       ::= { dnsResCache 5 }

   dnsResCacheRREntry OBJECT-TYPE
       SYNTAX      DnsResCacheRREntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "An entry in the resolvers's cache.  Rows may be created
               only by the resolver.  SNMP SET requests may be used to
               delete rows."
       INDEX     { dnsResCacheRRName,
                   dnsResCacheRRClass,
                   dnsResCacheRRType,
                   dnsResCacheRRIndex }

       ::= { dnsResCacheRRTable 1 }

   DnsResCacheRREntry ::=
       SEQUENCE {
           dnsResCacheRRName
               DnsNameAsIndex,
           dnsResCacheRRClass
               DnsClass,
           dnsResCacheRRType
               DnsType,
           dnsResCacheRRTTL
               DnsTime,
           dnsResCacheRRElapsedTTL
               DnsTime,
           dnsResCacheRRSource
               IpAddress,
           dnsResCacheRRData
               OCTET STRING,
           dnsResCacheRRStatus
               RowStatus,
           dnsResCacheRRIndex
               Integer32,
           dnsResCacheRRPrettyName
               DnsName
       }

   dnsResCacheRRName OBJECT-TYPE
       SYNTAX      DnsNameAsIndex
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "Owner name of the Resource Record in the cache which is
               identified in this row of the table.  As described in
               RFC-1034, the owner of the record is the domain name
               were the RR is found."
       REFERENCE
               "RFC-1034 section 3.6."
       ::= { dnsResCacheRREntry 1 }

   dnsResCacheRRClass OBJECT-TYPE
       SYNTAX      DnsClass
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS class of the Resource Record in the cache which is
               identified in this row of the table."
       ::= { dnsResCacheRREntry 2 }

   dnsResCacheRRType OBJECT-TYPE
       SYNTAX      DnsType
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS type of the Resource Record in the cache which is
               identified in this row of the table."
       ::= { dnsResCacheRREntry 3 }

   dnsResCacheRRTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Time-To-Live of RR in DNS cache.  This is the initial
               TTL value which was received with the RR when it was
               originally received."
       ::= { dnsResCacheRREntry 4 }

   dnsResCacheRRElapsedTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Elapsed seconds since RR was received."
       ::= { dnsResCacheRREntry 5 }

   dnsResCacheRRSource OBJECT-TYPE
       SYNTAX      IpAddress
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Host from which RR was received, 0.0.0.0 if unknown."
       ::= { dnsResCacheRREntry 6 }

   dnsResCacheRRData OBJECT-TYPE
       SYNTAX      OCTET STRING
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "RDATA portion of a cached RR.  The value is in the
               format defined for the particular DNS class and type of
               the resource record."
       REFERENCE
               "RFC-1035 section 3.2.1."
       ::= { dnsResCacheRREntry 7 }

   dnsResCacheRRStatus OBJECT-TYPE
       SYNTAX      RowStatus
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status column for the resolver cache table.  Since only
               the agent (DNS resolver) creates rows in this table, the
               only values that a manager may write to this variable
               are active(1) and destroy(6)."
       ::= { dnsResCacheRREntry 8 }

   dnsResCacheRRIndex OBJECT-TYPE
       SYNTAX      Integer32
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "A value which makes entries in the table unique when the
               other index values (dnsResCacheRRName,
               dnsResCacheRRClass, and dnsResCacheRRType) do not
               provide a unique index."
       ::= { dnsResCacheRREntry 9 }

   dnsResCacheRRPrettyName OBJECT-TYPE
       SYNTAX      DnsName
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Name of the RR at this row in the table.  This is
               identical to the dnsResCacheRRName variable, except that
               character case is preserved in this variable, per DNS
               conventions."
       REFERENCE
               "RFC-1035 section 2.3.3."
       ::= { dnsResCacheRREntry 10 }

   -- Resolver Negative Cache Group

   dnsResNCacheStatus OBJECT-TYPE
       SYNTAX      INTEGER { enabled(1), disabled(2), clear(3) }
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status/action for the resolver's negative response
               cache.

               enabled(1) means that the use of the negative response
               cache is allowed.  Query operations can return this
               state.

               disabled(2) means that the negative response cache is
               not being used.  Query operations can return this state.

               Setting this variable to clear(3) deletes the entire
               contents of the resolver's negative response cache.  The
               status will retain its previous value from before the
               clear operation (i.e., enabled(1) or disabled(2)).  The
               value of clear(3) can NOT be returned by a query
               operation."
       ::= { dnsResNCache 1 }

   dnsResNCacheMaxTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Maximum Time-To-Live for cached authoritative errors.
               If the resolver does not implement a TTL ceiling, the
               value of this field should be zero."
       ::= { dnsResNCache 2 }

   dnsResNCacheGoodNCaches OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of authoritative errors the resolver has cached
               successfully."
       ::= { dnsResNCache 3 }

   dnsResNCacheBadNCaches OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of authoritative errors the resolver would have
               liked to cache but was unable to because the appropriate
               SOA RR was not supplied or looked suspicious."
       REFERENCE
               "RFC-1034 section 4.3.4."
       ::= { dnsResNCache 4 }

   -- Resolver Negative Cache Table

   dnsResNCacheErrTable OBJECT-TYPE
       SYNTAX      SEQUENCE OF DnsResNCacheErrEntry
       MAX-ACCESS  not-accessible
       STATUS      current

       DESCRIPTION
               "The resolver's negative response cache.  This table
               contains information about authoritative errors that
               have been cached by the resolver."
       ::= { dnsResNCache 5 }

   dnsResNCacheErrEntry OBJECT-TYPE
       SYNTAX      DnsResNCacheErrEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "An entry in the resolver's negative response cache
               table.  Only the resolver can create rows.  SNMP SET
               requests may be used to delete rows."
       INDEX     { dnsResNCacheErrQName,
                   dnsResNCacheErrQClass,
                   dnsResNCacheErrQType,
                   dnsResNCacheErrIndex }
       ::= { dnsResNCacheErrTable 1 }

   DnsResNCacheErrEntry ::=
       SEQUENCE {
           dnsResNCacheErrQName
               DnsNameAsIndex,
           dnsResNCacheErrQClass
               DnsQClass,
           dnsResNCacheErrQType
               DnsQType,
           dnsResNCacheErrTTL
               DnsTime,
           dnsResNCacheErrElapsedTTL
               DnsTime,
           dnsResNCacheErrSource
               IpAddress,
           dnsResNCacheErrCode
               INTEGER,
           dnsResNCacheErrStatus
               RowStatus,
           dnsResNCacheErrIndex
               Integer32,
           dnsResNCacheErrPrettyName
               DnsName
       }

   dnsResNCacheErrQName OBJECT-TYPE
       SYNTAX      DnsNameAsIndex
       MAX-ACCESS  not-accessible
       STATUS      current

       DESCRIPTION
               "QNAME associated with a cached authoritative error."
       REFERENCE
               "RFC-1034 section 3.7.1."
       ::= { dnsResNCacheErrEntry 1 }

   dnsResNCacheErrQClass OBJECT-TYPE
       SYNTAX      DnsQClass
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS QCLASS associated with a cached authoritative
               error."
       ::= { dnsResNCacheErrEntry 2 }

   dnsResNCacheErrQType OBJECT-TYPE
       SYNTAX      DnsQType
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
               "DNS QTYPE associated with a cached authoritative error."
       ::= { dnsResNCacheErrEntry 3 }

   dnsResNCacheErrTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Time-To-Live of a cached authoritative error at the time
               of the error, it should not be decremented by the number
               of seconds since it was received.  This should be the
               TTL as copied from the MINIMUM field of the SOA that
               accompanied the authoritative error, or a smaller value
               if the resolver implements a ceiling on negative
               response cache TTLs."
       REFERENCE
               "RFC-1034 section 4.3.4."
       ::= { dnsResNCacheErrEntry 4 }

   dnsResNCacheErrElapsedTTL OBJECT-TYPE
       SYNTAX      DnsTime
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Elapsed seconds since authoritative error was received."
       ::= { dnsResNCacheErrEntry 5 }

   dnsResNCacheErrSource OBJECT-TYPE
       SYNTAX      IpAddress
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Host which sent the authoritative error, 0.0.0.0 if
               unknown."
       ::= { dnsResNCacheErrEntry 6 }

   dnsResNCacheErrCode OBJECT-TYPE
       SYNTAX      INTEGER { nonexistantName(1), noData(2), other(3) }
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "The authoritative error that has been cached:

               nonexistantName(1) indicates an authoritative name error
               (RCODE = 3).

               noData(2) indicates an authoritative response with no
               error (RCODE = 0) and no relevant data.

               other(3) indicates some other cached authoritative
               error.  At present, no such errors are known to exist."
       ::= { dnsResNCacheErrEntry 7 }

   dnsResNCacheErrStatus OBJECT-TYPE
       SYNTAX      RowStatus
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
               "Status column for the resolver negative response cache
               table.  Since only the agent (DNS resolver) creates rows
               in this table, the only values that a manager may write
               to this variable are active(1) and destroy(6)."
       ::= { dnsResNCacheErrEntry 8 }

   dnsResNCacheErrIndex OBJECT-TYPE
       SYNTAX      Integer32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "A value which makes entries in the table unique when the
               other index values (dnsResNCacheErrQName,
               dnsResNCacheErrQClass, and dnsResNCacheErrQType) do not
               provide a unique index."
       ::= { dnsResNCacheErrEntry 9 }

   dnsResNCacheErrPrettyName OBJECT-TYPE
       SYNTAX      DnsName
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "QNAME associated with this row in the table.  This is
               identical to the dnsResNCacheErrQName variable, except
               that character case is preserved in this variable, per
               DNS conventions."
       REFERENCE
               "RFC-1035 section 2.3.3."
       ::= { dnsResNCacheErrEntry 10 }


   -- Resolver Optional Counters Group

   dnsResOptCounterReferals OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of responses which were received from servers
               redirecting query to another server."
       ::= { dnsResOptCounter 1 }

   dnsResOptCounterRetrans OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number requests retransmitted for all reasons."
       ::= { dnsResOptCounter 2 }

   dnsResOptCounterNoResponses OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of queries that were retransmitted because of no
               response."
       ::= { dnsResOptCounter 3 }

   dnsResOptCounterRootRetrans OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of queries that were retransmitted that were to

               root servers."
       ::= { dnsResOptCounter 4 }

   dnsResOptCounterInternals OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of requests internally generated by the
               resolver."
       ::= { dnsResOptCounter 5 }

   dnsResOptCounterInternalTimeOuts OBJECT-TYPE
       SYNTAX      Counter32
       MAX-ACCESS  read-only
       STATUS      current
       DESCRIPTION
               "Number of requests internally generated which timed
               out."
       ::= { dnsResOptCounter 6 }


   -- SNMPv2 groups.

   dnsResMIBGroups         OBJECT IDENTIFIER ::= { dnsResMIB 2 }

   dnsResConfigGroup OBJECT-GROUP
       OBJECTS   { dnsResConfigImplementIdent,
                   dnsResConfigService,
                   dnsResConfigMaxCnames,
                   dnsResConfigSbeltAddr,
                   dnsResConfigSbeltName,
                   dnsResConfigSbeltRecursion,
                   dnsResConfigSbeltPref,
                   dnsResConfigSbeltSubTree,
                   dnsResConfigSbeltClass,
                   dnsResConfigSbeltStatus,
                   dnsResConfigUpTime,
                   dnsResConfigResetTime }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing basic configuration
               information for a DNS resolver implementation."
       ::= { dnsResMIBGroups 1 }

   dnsResCounterGroup OBJECT-GROUP
       OBJECTS   { dnsResCounterByOpcodeCode,
                   dnsResCounterByOpcodeQueries,

                   dnsResCounterByOpcodeResponses,
                   dnsResCounterByRcodeCode,
                   dnsResCounterByRcodeResponses,
                   dnsResCounterNonAuthDataResps,
                   dnsResCounterNonAuthNoDataResps,
                   dnsResCounterMartians,
                   dnsResCounterRecdResponses,
                   dnsResCounterUnparseResps,
                   dnsResCounterFallbacks }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing basic instrumentation
               of a DNS resolver implementation."
       ::= { dnsResMIBGroups 2 }

   dnsResLameDelegationGroup OBJECT-GROUP
       OBJECTS   { dnsResLameDelegationOverflows,
                   dnsResLameDelegationSource,
                   dnsResLameDelegationName,
                   dnsResLameDelegationClass,
                   dnsResLameDelegationCounts,
                   dnsResLameDelegationStatus }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing instrumentation of
               `lame delegation' failures."
       ::= { dnsResMIBGroups 3 }


   dnsResCacheGroup OBJECT-GROUP
       OBJECTS   { dnsResCacheStatus,
                   dnsResCacheMaxTTL,
                   dnsResCacheGoodCaches,
                   dnsResCacheBadCaches,
                   dnsResCacheRRName,
                   dnsResCacheRRClass,
                   dnsResCacheRRType,
                   dnsResCacheRRTTL,
                   dnsResCacheRRElapsedTTL,
                   dnsResCacheRRSource,
                   dnsResCacheRRData,
                   dnsResCacheRRStatus,
                   dnsResCacheRRIndex,
                   dnsResCacheRRPrettyName }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing access to and control
               of a DNS resolver's cache."

       ::= { dnsResMIBGroups 4 }

   dnsResNCacheGroup OBJECT-GROUP
       OBJECTS   { dnsResNCacheStatus,
                   dnsResNCacheMaxTTL,
                   dnsResNCacheGoodNCaches,
                   dnsResNCacheBadNCaches,
                   dnsResNCacheErrQName,
                   dnsResNCacheErrQClass,
                   dnsResNCacheErrQType,
                   dnsResNCacheErrTTL,
                   dnsResNCacheErrElapsedTTL,
                   dnsResNCacheErrSource,
                   dnsResNCacheErrCode,
                   dnsResNCacheErrStatus,
                   dnsResNCacheErrIndex,
                   dnsResNCacheErrPrettyName }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing access to and control
               of a DNS resolver's negative response cache."
       ::= { dnsResMIBGroups 5 }

   dnsResOptCounterGroup OBJECT-GROUP
       OBJECTS   { dnsResOptCounterReferals,
                   dnsResOptCounterRetrans,
                   dnsResOptCounterNoResponses,
                   dnsResOptCounterRootRetrans,
                   dnsResOptCounterInternals,
                   dnsResOptCounterInternalTimeOuts }
       STATUS      current
       DESCRIPTION
               "A collection of objects providing further
               instrumentation applicable to many but not all DNS
               resolvers."
       ::= { dnsResMIBGroups 6 }


   -- Compliances.

   dnsResMIBCompliances OBJECT IDENTIFIER ::= { dnsResMIB 3 }

   dnsResMIBCompliance MODULE-COMPLIANCE
       STATUS      current
       DESCRIPTION
               "The compliance statement for agents implementing the DNS
               resolver MIB extensions."
       MODULE -- This MIB module

           MANDATORY-GROUPS { dnsResConfigGroup, dnsResCounterGroup }
           GROUP   dnsResCacheGroup
           DESCRIPTION
               "The resolver cache group is mandatory for resolvers that
               implement a cache."
           GROUP   dnsResNCacheGroup
           DESCRIPTION
               "The resolver negative cache group is mandatory for
               resolvers that implement a negative response cache."
           GROUP   dnsResLameDelegationGroup
           DESCRIPTION
               "The lame delegation group is unconditionally optional."
           GROUP   dnsResOptCounterGroup
           DESCRIPTION
               "The optional counters group is unconditionally
               optional."
           OBJECT  dnsResConfigMaxCnames
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResConfigSbeltName
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResConfigSbeltRecursion
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResConfigSbeltPref
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResConfigReset
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResCacheStatus
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResCacheMaxTTL
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
           OBJECT  dnsResNCacheStatus
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."

           OBJECT  dnsResNCacheMaxTTL
           MIN-ACCESS      read-only
           DESCRIPTION
               "This object need not be writable."
       ::= { dnsResMIBCompliances 1 }

   END

5.  Acknowledgements

   This document is the result of work undertaken the by DNS working
   group.  The authors would particularly like to thank the following
   people for their contributions to this document: Philip Almquist,
   Frank Kastenholz (FTP Software), Joe Peck (DEC), Dave Perkins
   (SynOptics), Win Treese (DEC), and Mimi Zohar (IBM).

6.  References

   [1] Mockapetris, P., "Domain Names -- Concepts and Facilities", STD
       13, RFC 1034, USC/Information Sciences Institute, November 1987.

   [2] Mockapetris, P., "Domain Names -- Implementation and
       Specification", STD 13, RFC 1035, USC/Information Sciences
       Institute, November 1987.

   [3] Braden, R., Editor, "Requirements for Internet Hosts --
       Application and Support, STD 3, RFC 1123, USC/Information
       Sciences Institute, October 1989.

   [4] Rose, M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", STD 16, RFC
       1155, Performance Systems International, Hughes LAN Systems, May
       1990.

   [5] McCloghrie, K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based internets", RFC 1156, Hughes
       LAN Systems, Performance Systems International, May 1990.

   [6] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.

   [7] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, RFC 1212, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [8] McCloghrie, K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based internets: MIB-II", STD 17,
       RFC 1213, Hughes LAN Systems, Performance Systems International,
       March 1991.

   [9] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure
       of Management Information for version 2 of the Simple Network
       Management Protocol (SNMPv2)", RFC 1442, SNMP Research, Inc.,
       Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

  [10] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Textual
       Conventions for version 2 of the the Simple Network Management
       Protocol (SNMPv2)", RFC 1443, SNMP Research, Inc., Hughes LAN
       Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

  [11] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser,
       "Conformance Statements for version 2 of the the Simple Network
       Management Protocol (SNMPv2)", RFC 1444, SNMP Research, Inc.,
       Hughes LAN Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

  [12] Galvin, J., and K. McCloghrie, "Administrative Model for version
       2 of the Simple Network Management Protocol (SNMPv2)", RFC 1445,
       Trusted Information Systems, Hughes LAN Systems, April 1993.

  [13] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol
       Operations for version 2 of the Simple Network Management
       Protocol (SNMPv2)", RFC 1448, SNMP Research, Inc., Hughes LAN
       Systems, Dover Beach Consulting, Inc., Carnegie Mellon
       University, April 1993.

  [14] "Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1)",
       International Organization for Standardization, International
       Standard 8824, December 1987.

7.  Security Considerations

   Security issues are not discussed in this memo.

8.  Authors' Addresses

   Rob Austein
   Epilogue Technology Corporation
   268 Main Street, Suite 283
   North Reading, MA 01864
   USA

   Phone: +1-617-245-0804
   Fax:   +1-617-245-8122
   EMail: sra@epilogue.com


   Jon Saperia
   Digital Equipment Corporation
   110 Spit Brook Road
   ZKO1-3/H18
   Nashua, NH 03062-2698
   USA

   Phone: +1-603-881-0480
   Fax:   +1-603-881-0120
   EMail: saperia@zko.dec.com