RFC 4113 PROPOSED STANDARD SNMP · UDP · MANAGEMENT

UDP MIB: Management Information Base for the User Datagram Protocol (UDP)

The SNMP objects a router exposes so a manager can count UDP traffic and list every UDP endpoint it holds.

On rfc-editor.org ↗
PUBLISHED
June 2005
AUTHORS
B. Fenner, J. Flick
STREAM
IETF
BUILDS ON
RFC 2013 — UDP MIB, RFC 2454 — IP Version 6 Management Information Base for the User Datagram Protocol
UDP GROUP OID
{ mib-2 7 }
UDPMIB MODULE OID
{ mib-2 50 }
HIGH-CAPACITY COUNTERS
For more than 1 million datagrams per second
ENDPOINT TABLE INDEX COLUMNS
7
ADDRESS OCTET LIMIT
111 octets for the local and remote addresses together
DOI
10.17487/RFC4113
ERRATA
Reported errata

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
Network Working Group                                          B. Fenner
Request for Comments: 4113                          AT&T Labs - Research
Obsoletes: 2454, 2013                                           J. Flick
Category: Standards Track                        Hewlett-Packard Company
                                                               June 2005


    Management Information Base for the User Datagram Protocol (UDP)

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.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   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 managed objects used for implementations
   of the User Datagram Protocol (UDP) in an IP version independent
   manner.  This memo obsoletes RFCs 2013 and 2454.

Table of Contents

   1.  The Internet-Standard Management Framework . . . . . . . . . .  2
   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  2
       2.1.  Relationship to Other MIBs . . . . . . . . . . . . . . .  3
             2.1.1.  Relationship to RFC1213-MIB  . . . . . . . . . .  3
             2.1.2.  Relationship to the IPV6-UDP-MIB . . . . . . . .  3
             2.1.3.  Relationship to HOST-RESOURCES-MIB and
                     SYSAPPL-MIB. . . . . . . . . . . . . . . . . . .  4
   3.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
   5.  Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 15
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
       8.1.  Normative References . . . . . . . . . . . . . . . . . . 17
       8.2.  Informative References . . . . . . . . . . . . . . . . . 18

1.  The Internet-Standard Management Framework

   For a detailed overview of the documents that describe the current
   Internet-Standard Management Framework, please refer to section 7 of
   RFC 3410 [RFC3410].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  MIB objects are generally
   accessed through the Simple Network Management Protocol (SNMP).
   Objects in the MIB are defined using the mechanisms defined in the
   Structure of Management Information (SMI).  This memo specifies a MIB
   module that is compliant to the SMIv2, which is described in STD 58,
   RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
   [RFC2580].

2.  Overview

   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 managed objects used for implementations
   of the User Datagram Protocol (UDP), as defined in RFC 768 [RFC0768],
   in an IP version independent manner.

   The current UDP-MIB defined in this memo consists of one table and a
   group of scalars:

   o  The udp group of scalars reports parameters and statistics of a
      UDP protocol engine.  Two scalars, udpHCInDatagrams and
      udpHCOutDatagrams, have been added to this group since the
      publication of RFC 2013 [RFC2013] in order to provide high-
      capacity counters for fast networks.  Discontinuities in the
      values of the counters in this group are indicated by
      discontinuities in the value of the sysUpTime object, which is
      defined in RFC 3418 [RFC3418].

   o  The udpEndpointTable provides access to status information for all
      UDP endpoints handled by a UDP protocol engine.  The table
      provides for strictly listening endpoints, as with the historical
      udpTable, and also for "connected" UDP endpoints, which only
      accept packets from a given remote system.  It also reports
      identification of the operating system level processes that handle
      UDP connections.  Addresses and ports of UDP endpoints in this
      table are represented using the InetAddressType, InetAddress, and
      InetPortNumber textual conventions defined in RFC 4001 [RFC4001].

2.1.  Relationship to Other MIBs

   This section discusses the relationship of this UDP-MIB module to
   other MIB modules.

2.1.1.  Relationship to RFC1213-MIB

   UDP related MIB objects were originally defined as part of the
   RFC1213-MIB, defined in RFC 1213 [RFC1213].  The UDP related objects
   of the RFC1213-MIB were later copied into a separate MIB module and
   published in RFC 2013 [RFC2013] in SMIv2 format.

   The previous versions of the UDP-MIB both defined the udpTable, which
   has been deprecated for basically two reasons:

   (1) The udpTable only supports IPv4.

       The current approach in the IETF is to write IP version neutral
       MIBs rather than have different definitions for various version
       of IP.  This reduces the amount of overhead when new objects are
       introduced, since there is only one place to add them.  Hence,
       the approach taken in RFC 2454 [RFC2454] of having separate
       tables is not continued.

   (2) The udpTable does not permit describing "connected" UDP
       endpoints.

       It turns out that "connected" endpoints tend to have a different
       behaviour and management access pattern from those of listening
       endpoints.  Adding remote endpoint information to the
       udpEndpointTable thus allows for the addition of specific status
       and statistic objects for "connected" endpoints and connections.

2.1.2.  Relationship to the IPV6-UDP-MIB

   The IPV6-UDP-MIB, defined in RFC 2454 [RFC2454], has been moved to
   Historic because the approach of having separate IP version specific
   tables is not followed anymore.  Implementation of RFC 2454 is thus
   not suggested anymore.

   Note that because scoped addresses are now represented using the
   IPv4z and IPv6z address types, there is no longer a need to
   explicitly include the ifIndex in the index clause of the
   udpEndpointTable.  This is a change from the use of ipv6UdpIfIndex in
   RFC 2454.

2.1.3.  Relationship to HOST-RESOURCES-MIB and SYSAPPL-MIB

   The udpEndpointTable reports the identification of the operating
   system level process that handles a connection or a listening
   endpoint.  The value is reported as an Unsigned32, which is expected
   to be the same as the hrSWRunIndex of the HOST-RESOURCES-MIB
   [RFC2790] (if the value is smaller than 2147483647) or the
   sysApplElmtRunIndex of the SYSAPPL-MIB [RFC2287].  This allows
   management applications to identify the UDP connections that belong
   to an operating system level process, which has proven valuable in
   operational environments.

3.  Definitions

   UDP-MIB DEFINITIONS ::= BEGIN

   IMPORTS
       MODULE-IDENTITY, OBJECT-TYPE, Integer32, Counter32, Counter64,
       Unsigned32, IpAddress, mib-2       FROM SNMPv2-SMI
       MODULE-COMPLIANCE, OBJECT-GROUP    FROM SNMPv2-CONF
       InetAddress, InetAddressType,
       InetPortNumber                     FROM INET-ADDRESS-MIB;

   udpMIB MODULE-IDENTITY
       LAST-UPDATED "200505200000Z"  -- May 20, 2005
       ORGANIZATION
              "IETF IPv6 Working Group
               http://www.ietf.org/html.charters/ipv6-charter.html"
       CONTACT-INFO
              "Bill Fenner (editor)

               AT&T Labs -- Research
               75 Willow Rd.
               Menlo Park, CA 94025

               Phone: +1 650 330-7893
               Email: <fenner@research.att.com>

               John Flick (editor)

               Hewlett-Packard Company
               8000 Foothills Blvd. M/S 5557
               Roseville, CA 95747

               Phone: +1 916 785 4018
               Email: <john.flick@hp.com>

               Send comments to <ipv6@ietf.org>"

       DESCRIPTION
              "The MIB module for managing UDP implementations.
               Copyright (C) The Internet Society (2005).  This
               version of this MIB module is part of RFC 4113;
               see the RFC itself for full legal notices."
       REVISION      "200505200000Z"  -- May 20, 2005
       DESCRIPTION
              "IP version neutral revision, incorporating the
               following revisions:

               - Added udpHCInDatagrams and udpHCOutDatagrams in order
                 to provide high-capacity counters for fast networks.
               - Added text to the descriptions of all counter objects
                 to indicate how discontinuities are detected.
               - Deprecated the IPv4-specific udpTable and replaced it
                 with the version neutral udpEndpointTable.  This
                 table includes support for connected UDP endpoints
                 and support for identification of the operating
                 system process associated with a UDP endpoint.
               - Deprecated the udpGroup and replaced it with object
                 groups representing the current set of objects.
               - Deprecated udpMIBCompliance and replaced it with
                 udpMIBCompliance2, which includes the compliance
                 information for the new object groups.

               This version published as RFC 4113."
       REVISION      "199411010000Z"    -- November 1, 1994
       DESCRIPTION
              "Initial SMIv2 version, published as RFC 2013."
       REVISION      "199103310000Z"    -- March 31, 1991
       DESCRIPTION
              "The initial revision of this MIB module was part of
               MIB-II, published as RFC 1213."
       ::= { mib-2 50 }

   -- the UDP group

   udp      OBJECT IDENTIFIER ::= { mib-2 7 }

   udpInDatagrams OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The total number of UDP datagrams delivered to UDP
               users.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 1 }

   udpNoPorts OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The total number of received UDP datagrams for which
               there was no application at the destination port.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 2 }

   udpInErrors OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The number of received UDP datagrams that could not be
               delivered for reasons other than the lack of an
               application at the destination port.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 3 }

   udpOutDatagrams OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The total number of UDP datagrams sent from this
               entity.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 4 }

   udpHCInDatagrams OBJECT-TYPE
       SYNTAX     Counter64
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The total number of UDP datagrams delivered to UDP
               users, for devices that can receive more than 1
               million UDP datagrams per second.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 8 }

   udpHCOutDatagrams OBJECT-TYPE
       SYNTAX     Counter64
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The total number of UDP datagrams sent from this
               entity, for devices that can transmit more than 1
               million UDP datagrams per second.

               Discontinuities in the value of this counter can occur
               at re-initialization of the management system, and at
               other times as indicated by discontinuities in the
               value of sysUpTime."
       ::= { udp 9 }

   --
   -- { udp 6 } was defined as the ipv6UdpTable in RFC2454's
   -- IPV6-UDP-MIB.  This RFC obsoletes RFC 2454, so { udp 6 } is
   -- obsoleted.
   --

   -- The UDP "Endpoint" table.

   udpEndpointTable OBJECT-TYPE
       SYNTAX     SEQUENCE OF UdpEndpointEntry
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "A table containing information about this entity's UDP
               endpoints on which a local application is currently
               accepting or sending datagrams.

               The address type in this table represents the address
               type used for the communication, irrespective of the
               higher-layer abstraction.  For example, an application
               using IPv6 'sockets' to communicate via IPv4 between
               ::ffff:10.0.0.1 and ::ffff:10.0.0.2 would use
               InetAddressType ipv4(1).

               Unlike the udpTable in RFC 2013, this table also allows
               the representation of an application that completely
               specifies both local and remote addresses and ports.  A
               listening application is represented in three possible
               ways:

               1) An application that is willing to accept both IPv4
                  and IPv6 datagrams is represented by a
                  udpEndpointLocalAddressType of unknown(0) and a
                  udpEndpointLocalAddress of ''h (a zero-length
                  octet-string).

               2) An application that is willing to accept only IPv4
                  or only IPv6 datagrams is represented by a
                  udpEndpointLocalAddressType of the appropriate
                  address type and a udpEndpointLocalAddress of
                  '0.0.0.0' or '::' respectively.

               3) An application that is listening for datagrams only
                  for a specific IP address but from any remote
                  system is represented by a
                  udpEndpointLocalAddressType of the appropriate
                  address type, with udpEndpointLocalAddress
                  specifying the local address.

               In all cases where the remote is a wildcard, the
               udpEndpointRemoteAddressType is unknown(0), the
               udpEndpointRemoteAddress is ''h (a zero-length
               octet-string), and the udpEndpointRemotePort is 0.

               If the operating system is demultiplexing UDP packets
               by remote address and port, or if the application has
               'connected' the socket specifying a default remote
               address and port, the udpEndpointRemote* values should
               be used to reflect this."
       ::= { udp 7 }

   udpEndpointEntry OBJECT-TYPE
       SYNTAX     UdpEndpointEntry
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "Information about a particular current UDP endpoint.

               Implementers need to be aware that if the total number
               of elements (octets or sub-identifiers) in
               udpEndpointLocalAddress and udpEndpointRemoteAddress
               exceeds 111, then OIDs of column instances in this table
               will have more than 128 sub-identifiers and cannot be
               accessed using SNMPv1, SNMPv2c, or SNMPv3."
       INDEX   { udpEndpointLocalAddressType,
                 udpEndpointLocalAddress,
                 udpEndpointLocalPort,
                 udpEndpointRemoteAddressType,
                 udpEndpointRemoteAddress,
                 udpEndpointRemotePort,
                 udpEndpointInstance }
       ::= { udpEndpointTable 1 }

   UdpEndpointEntry ::= SEQUENCE {
           udpEndpointLocalAddressType   InetAddressType,
           udpEndpointLocalAddress       InetAddress,
           udpEndpointLocalPort          InetPortNumber,
           udpEndpointRemoteAddressType  InetAddressType,
           udpEndpointRemoteAddress      InetAddress,
           udpEndpointRemotePort         InetPortNumber,
           udpEndpointInstance           Unsigned32,
           udpEndpointProcess            Unsigned32
       }

   udpEndpointLocalAddressType OBJECT-TYPE
       SYNTAX     InetAddressType
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The address type of udpEndpointLocalAddress.  Only
               IPv4, IPv4z, IPv6, and IPv6z addresses are expected, or
               unknown(0) if datagrams for all local IP addresses are
               accepted."
       ::= { udpEndpointEntry 1 }

   udpEndpointLocalAddress OBJECT-TYPE
       SYNTAX     InetAddress
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The local IP address for this UDP endpoint.

               The value of this object can be represented in three
               possible ways, depending on the characteristics of the
               listening application:

               1. For an application that is willing to accept both
                  IPv4 and IPv6 datagrams, the value of this object
                  must be ''h (a zero-length octet-string), with
                  the value of the corresponding instance of the
                  udpEndpointLocalAddressType object being unknown(0).

               2. For an application that is willing to accept only IPv4
                  or only IPv6 datagrams, the value of this object
                  must be '0.0.0.0' or '::', respectively, while the
                  corresponding instance of the
                  udpEndpointLocalAddressType object represents the
                  appropriate address type.

               3. For an application that is listening for data
                  destined only to a specific IP address, the value
                  of this object is the specific IP address for which
                  this node is receiving packets, with the
                  corresponding instance of the
                  udpEndpointLocalAddressType object representing the
                  appropriate address type.

               As this object is used in the index for the
               udpEndpointTable, implementors of this table should be
               careful not to create entries that would result in OIDs
               with more than 128 subidentifiers; else the information
               cannot be accessed using SNMPv1, SNMPv2c, or SNMPv3."
       ::= { udpEndpointEntry 2 }

   udpEndpointLocalPort OBJECT-TYPE
       SYNTAX     InetPortNumber
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The local port number for this UDP endpoint."
       ::= { udpEndpointEntry 3 }

   udpEndpointRemoteAddressType OBJECT-TYPE
       SYNTAX     InetAddressType
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The address type of udpEndpointRemoteAddress.  Only
               IPv4, IPv4z, IPv6, and IPv6z addresses are expected, or
               unknown(0) if datagrams for all remote IP addresses are
               accepted.  Also, note that some combinations of
               udpEndpointLocalAdressType and
               udpEndpointRemoteAddressType are not supported.  In
               particular, if the value of this object is not
               unknown(0), it is expected to always refer to the
               same IP version as udpEndpointLocalAddressType."
       ::= { udpEndpointEntry 4 }

   udpEndpointRemoteAddress OBJECT-TYPE
       SYNTAX     InetAddress
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The remote IP address for this UDP endpoint.  If
               datagrams from any remote system are to be accepted,
               this value is ''h (a zero-length octet-string).
               Otherwise, it has the type described by
               udpEndpointRemoteAddressType and is the address of the
               remote system from which datagrams are to be accepted
               (or to which all datagrams will be sent).

               As this object is used in the index for the
               udpEndpointTable, implementors of this table should be
               careful not to create entries that would result in OIDs
               with more than 128 subidentifiers; else the information
               cannot be accessed using SNMPv1, SNMPv2c, or SNMPv3."
       ::= { udpEndpointEntry 5 }

   udpEndpointRemotePort OBJECT-TYPE
       SYNTAX     InetPortNumber
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The remote port number for this UDP endpoint.  If
               datagrams from any remote system are to be accepted,
               this value is zero."
       ::= { udpEndpointEntry 6 }

   udpEndpointInstance OBJECT-TYPE
       SYNTAX     Unsigned32 (1..'ffffffff'h)
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The instance of this tuple.  This object is used to
               distinguish among multiple processes 'connected' to
               the same UDP endpoint.  For example, on a system
               implementing the BSD sockets interface, this would be
               used to support the SO_REUSEADDR and SO_REUSEPORT
               socket options."

       ::= { udpEndpointEntry 7 }

   udpEndpointProcess OBJECT-TYPE
       SYNTAX     Unsigned32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
              "The system's process ID for the process associated with
               this endpoint, or zero if there is no such process.
               This value is expected to be the same as
               HOST-RESOURCES-MIB::hrSWRunIndex or SYSAPPL-MIB::
               sysApplElmtRunIndex for some row in the appropriate
               tables."
       ::= { udpEndpointEntry 8 }

   -- The deprecated UDP Listener table

   -- The deprecated UDP listener table only contains information
   -- about this entity's IPv4 UDP end-points on which a local
   -- application is currently accepting datagrams.  It does not
   -- provide more detailed connection information, or information
   -- about IPv6 endpoints.

   udpTable OBJECT-TYPE
       SYNTAX     SEQUENCE OF UdpEntry
       MAX-ACCESS not-accessible
       STATUS     deprecated
       DESCRIPTION
              "A table containing IPv4-specific UDP listener
               information.  It contains information about all local
               IPv4 UDP end-points on which an application is
               currently accepting datagrams.  This table has been
               deprecated in favor of the version neutral
               udpEndpointTable."
       ::= { udp 5 }

   udpEntry OBJECT-TYPE
       SYNTAX     UdpEntry
       MAX-ACCESS not-accessible
       STATUS     deprecated
       DESCRIPTION
              "Information about a particular current UDP listener."
       INDEX   { udpLocalAddress, udpLocalPort }
       ::= { udpTable 1 }

   UdpEntry ::= SEQUENCE {
       udpLocalAddress   IpAddress,
       udpLocalPort      Integer32

   }

   udpLocalAddress OBJECT-TYPE
       SYNTAX     IpAddress
       MAX-ACCESS read-only
       STATUS     deprecated
       DESCRIPTION
              "The local IP address for this UDP listener.  In the
               case of a UDP listener that is willing to accept
               datagrams for any IP interface associated with the
               node, the value 0.0.0.0 is used."
       ::= { udpEntry 1 }

   udpLocalPort OBJECT-TYPE
       SYNTAX     Integer32 (0..65535)
       MAX-ACCESS read-only
       STATUS     deprecated
       DESCRIPTION
              "The local port number for this UDP listener."
       ::= { udpEntry 2 }

   -- conformance information

   udpMIBConformance OBJECT IDENTIFIER ::= { udpMIB 2 }
   udpMIBCompliances OBJECT IDENTIFIER ::= { udpMIBConformance 1 }
   udpMIBGroups      OBJECT IDENTIFIER ::= { udpMIBConformance 2 }

   -- compliance statements

   udpMIBCompliance2 MODULE-COMPLIANCE
       STATUS     current
       DESCRIPTION
              "The compliance statement for systems that implement
               UDP.

               There are a number of INDEX objects that cannot be
               represented in the form of OBJECT clauses in SMIv2, but
               for which we have the following compliance
               requirements, expressed in OBJECT clause form in this
               description clause:

               -- OBJECT      udpEndpointLocalAddressType
               -- SYNTAX      InetAddressType { unknown(0), ipv4(1),
               --                               ipv6(2), ipv4z(3),
               --                               ipv6z(4) }
               -- DESCRIPTION
               --     Support for dns(5) is not required.
               -- OBJECT      udpEndpointLocalAddress
               -- SYNTAX      InetAddress (SIZE(0|4|8|16|20))
               -- DESCRIPTION
               --     Support is only required for zero-length
               --     octet-strings, and for scoped and unscoped
               --     IPv4 and IPv6 addresses.
               -- OBJECT      udpEndpointRemoteAddressType
               -- SYNTAX      InetAddressType { unknown(0), ipv4(1),
               --                               ipv6(2), ipv4z(3),
               --                               ipv6z(4) }
               -- DESCRIPTION
               --     Support for dns(5) is not required.
               -- OBJECT      udpEndpointRemoteAddress
               -- SYNTAX      InetAddress (SIZE(0|4|8|16|20))
               -- DESCRIPTION
               --     Support is only required for zero-length
               --     octet-strings, and for scoped and unscoped
               --     IPv4 and IPv6 addresses.
              "
       MODULE  -- this module
            MANDATORY-GROUPS { udpBaseGroup, udpEndpointGroup }
            GROUP       udpHCGroup
            DESCRIPTION
                   "This group is mandatory for systems that
                    are capable of receiving or transmitting more than
                    1 million UDP datagrams per second.  1 million
                    datagrams per second will cause a Counter32 to
                    wrap in just over an hour."
       ::= { udpMIBCompliances 2 }

   udpMIBCompliance MODULE-COMPLIANCE
       STATUS     deprecated
       DESCRIPTION
              "The compliance statement for IPv4-only systems that
               implement UDP.  For IP version independence, this
               compliance statement is deprecated in favor of
               udpMIBCompliance2.  However, agents are still
               encouraged to implement these objects in order to
               interoperate with the deployed base of managers."
       MODULE  -- this module
           MANDATORY-GROUPS { udpGroup }
       ::= { udpMIBCompliances 1 }

   -- units of conformance

   udpGroup OBJECT-GROUP
       OBJECTS   { udpInDatagrams, udpNoPorts,
                   udpInErrors, udpOutDatagrams,
                   udpLocalAddress, udpLocalPort }

       STATUS     deprecated
       DESCRIPTION
              "The deprecated group of objects providing for
               management of UDP over IPv4."
       ::= { udpMIBGroups 1 }

   udpBaseGroup OBJECT-GROUP
       OBJECTS   { udpInDatagrams, udpNoPorts, udpInErrors,
                   udpOutDatagrams }
       STATUS     current
       DESCRIPTION
              "The group of objects providing for counters of UDP
               statistics."
       ::= { udpMIBGroups 2 }

   udpHCGroup OBJECT-GROUP
       OBJECTS   { udpHCInDatagrams, udpHCOutDatagrams }
       STATUS     current
       DESCRIPTION
              "The group of objects providing for counters of high
               speed UDP implementations."
       ::= { udpMIBGroups 3 }

   udpEndpointGroup OBJECT-GROUP
       OBJECTS    { udpEndpointProcess }
       STATUS     current
       DESCRIPTION
              "The group of objects providing for the IP version
               independent management of UDP 'endpoints'."
       ::= { udpMIBGroups 4 }

   END

4.  Acknowledgements

   This document contains a modified subset of RFC 1213 and replaces
   RFCs 2013 and 2454.  Acknowledgments are therefore due to the authors
   and editors of these documents for their excellent work.

5.  Contributors

   This document is an output of the IPv6 MIB revision team, and
   contributors to earlier versions of this document include:

      Bill Fenner, AT&T Labs -- Research
      Email: fenner@research.at.com
      Brian Haberman
      Email: brian@innovationslab.net

      Shawn A. Routhier, Wind River
      Email: sar@epilogue.com

      Juergen Schoenwalder, TU Braunschweig
      Email: schoenw@ibr.cs.tu-bs.de

      Dave Thaler, Microsoft
      Email: dthaler@windows.microsoft.com

   Much of Keith McCloghrie's text from RFC1213/RFC2013 remains in this
   document, and the structure of the MIB is due to him.

   Mike Daniele wrote the original IPv6 UDP MIB in RFC2454.

   Juergen Schoenwalder provided much of the text for section 2.

6.  Security Considerations

   There are no management objects defined in this MIB that have a MAX-
   ACCESS clause of read-write and/or read-create.  So, if this MIB is
   implemented correctly, then there is no risk that an intruder can
   alter or create any management objects of this MIB module via direct
   SNMP SET operations.

   Some of the readable objects in this MIB module (i.e., objects with a
   MAX-ACCESS other than not-accessible) may be considered sensitive or
   vulnerable in some network environments.  It is thus important to
   control even GET and/or NOTIFY access to these objects and possibly
   to even encrypt the values of these objects when sending them over
   the network via SNMP.  These are the tables and objects and their
   sensitivity/vulnerability:

   The indices of the udpEndpointTable and udpTable contain information
   on the listeners on an entity.  In particular, the
   udpEndpointLocalPort and udpLocalPort objects in the indices can be
   used to identify what ports are open on the machine and what attacks
   are likely to succeed, without the attacker having to run a port
   scanner.

   SNMP versions prior to SNMPv3 did not include adequate security.
   Even if the network itself is secure (for example by using IPSec),
   even then, there is no control as to who on the secure network is
   allowed to access and GET/SET (read/change/create/delete) the objects
   in this MIB module.

   It is recommended that the implementors consider the security
   features as provided by the SNMPv3 framework (see [RFC3410], section
   8), including full support for the SNMPv3 cryptographic mechanisms
   (for authentication and privacy).

   Furthermore, deployment of SNMP versions prior to SNMPv3 is NOT
   RECOMMENDED.  Instead, it is RECOMMENDED to deploy SNMPv3 and to
   enable cryptographic security.  It is then a customer/operator
   responsibility to ensure that the SNMP entity giving access to an
   instance of this MIB module is properly configured to give access to
   the objects only to those principals (users) that have legitimate
   rights to indeed GET or SET (change/create/delete) them.

7.  IANA Considerations

   The MIB module in this document uses the following IANA-assigned
   OBJECT IDENTIFIER values, recorded in the SMI Numbers registry:

         +------------+-------------------------+
         | Descriptor | OBJECT IDENTIFIER value |
         +------------+-------------------------+
         | udp        | { mib-2 7}              |
         | udpMIB     | { mib-2 50 }            |
         +------------+-------------------------+

8.  References

8.1.  Normative References

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              August 1980.

   [RFC2578]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Structure of Management Information Version 2 (SMIv2)",
              STD 58, RFC 2578, April 1999.

   [RFC2579]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Textual Conventions for SMIv2", STD 58, RFC 2579, April
              1999.

   [RFC2580]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Conformance Statements for SMIv2", STD 58, RFC 2580,
              April 1999.

   [RFC3418]  Presuhn, R., "Management Information Base (MIB) for the
              Simple Network Management Protocol (SNMP)", STD 62, RFC
              3418, December 2002.

   [RFC4001]  Daniele, M., Haberman, B., Routhier, S., and J.
              Schoenwaelder, "Textual Conventions for Internet Network
              Addresses", RFC 4001, February 2005.

8.2.  Informative References

   [RFC1213]  McCloghrie, K. and M. Rose, "Management Information Base
              for Network Management of TCP/IP-based internets:MIB-II",
              STD 17, RFC 1213, March 1991.

   [RFC2013]  McCloghrie, K., "SNMPv2 Management Information Base for
              the User Datagram Protocol using SMIv2", RFC 2013,
              November 1996.

   [RFC2287]  Krupczak, C. and J. Saperia, "Definitions of System-Level
              Managed Objects for Applications", RFC 2287, February
              1998.

   [RFC2454]  Daniele, M., "IP Version 6 Management Information Base for
              the User Datagram Protocol", RFC 2454, December 1998.

   [RFC2790]  Waldbusser, S. and P. Grillo, "Host Resources MIB", RFC
              2790, March 2000.

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for Internet-
              Standard Management Framework", RFC 3410, December 2002.

Authors' Addresses

   Bill Fenner
   AT&T Labs -- Research
   75 Willow Rd
   Menlo Park, CA  94025
   USA

   EMail: fenner@research.att.com


   John Flick
   Hewlett-Packard Company
   8000 Foothills Blvd. M/S 5557
   Roseville, CA  95747-5557
   USA

   EMail: john.flick@hp.com

Full Copyright Statement

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Acknowledgement

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ISO Plain Language

On this page
PROBLEMA network manager needs to know how much UDP traffic a host is carrying and which UDP sockets are open, but the original SNMP objects for UDP only described IPv4 and could not describe a socket bound to one remote address.
MECHANISMThe document defines a MIB module with one table, the udpEndpointTable, whose rows are indexed by the local and remote address type, address and port, and a group of counters such as udpInDatagrams and udpHCOutDatagrams.
WHAT IT REPLACESOne table now covers both IP versions and both listening and connected endpoints, and it reports which operating system process owns each endpoint. The module obsoletes RFC 2013 and RFC 2454, whose IPv6 table has been moved to Historic.

§1The Internet-Standard Management Framework

Managed objects are reached through a virtual information store called the Management Information Base (MIB), and they are generally accessed with the Simple Network Management Protocol (SNMP). The objects are defined using the mechanisms of the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant with SMIv2, which is described in RFC 2578, RFC 2579 and RFC 2580. The wider management framework is described in Section 7 of RFC 3410.

For a reader who has never used SNMP: a managed object is a named value that a device exposes, such as a counter of packets sent. The MIB is the catalogue that gives those values names and types. A manager reads them over SNMP by walking the catalogue, and SNMPv3 adds authentication and privacy to that exchange.

A managed object is a named value that a device exposes, such as a counter of packets sent. The MIB is the catalogue that gives those values names and types, and a manager reads them over SNMP by walking that catalogue.

§2Overview: The UDP MIB

The memo defines the part of the MIB that describes implementations of the User Datagram Protocol, as defined in RFC 768, in an IP version independent manner. The module consists of one table and a group of scalars.

The udp group of scalars reports parameters and statistics of a UDP protocol engine. Two of them, udpHCInDatagrams and udpHCOutDatagrams, were added after RFC 2013 to provide high-capacity counters for fast networks. Discontinuities in the values of the counters in this group are indicated by discontinuities in the value of the sysUpTime object, which is defined in RFC 3418.

The udpEndpointTable gives access to status information for all the UDP endpoints a UDP protocol engine handles. It covers strictly listening endpoints, as the historical udpTable did, and also connected endpoints, which accept packets only from a given remote system. It also reports which operating system level process handles each UDP connection. Addresses and ports in the table use the InetAddressType, InetAddress and InetPortNumber textual conventions defined in RFC 4001.

The module has two parts. A group of counters says how much UDP traffic the device handled. A table lists every UDP endpoint it holds, whether the endpoint is listening for anyone or bound to one particular remote host, and which program on the machine is using it.

§2.1Relationship to Other MIBs

UDP related objects were originally part of the RFC1213-MIB, defined in RFC 1213, and were later copied into a separate module and published in SMIv2 form as RFC 2013. Both earlier versions of the UDP-MIB defined the udpTable, which is deprecated for two reasons.

The first is that the udpTable supports IPv4 only. The approach in the IETF is to write IP version neutral MIBs rather than separate definitions for each version of IP, so that new objects are added in one place; the approach of RFC 2454 with separate tables is therefore not continued. The second is that the udpTable cannot describe connected UDP endpoints. Connected endpoints behave differently from listening ones and are managed differently, so adding the remote endpoint information to the udpEndpointTable leaves room for status and statistic objects specific to them.

The IPV6-UDP-MIB of RFC 2454 has been moved to Historic, because the approach of separate IP version specific tables is no longer followed, and implementing RFC 2454 is no longer suggested. Because scoped addresses are now represented with the IPv4z and IPv6z address types, there is no longer a need to include the interface index in the index of the udpEndpointTable, which is a change from the use of ipv6UdpIfIndex in RFC 2454.

The table reports the identification of the operating system level process that handles a connection or a listening endpoint, as an Unsigned32 value. It is expected to be the same as the hrSWRunIndex of the HOST-RESOURCES-MIB in RFC 2790, if the value is smaller than 2147483647, or the sysApplElmtRunIndex of the SYSAPPL-MIB in RFC 2287. This lets a management application identify the UDP connections that belong to a particular program, which has proved valuable in operational environments.

The old table only understood IPv4 and could not describe a socket that talks to one fixed remote host, so it is deprecated. This document replaces it with one table that works for both IP versions, and it also links each endpoint to the program on the machine that owns it, using the identifiers that other management modules already use.

THE DEPRECATED TABLE AND THE CURRENT ONE
Point of differenceudpTable, deprecatedudpEndpointTable, current
IP versionsIPv4 only.IP version neutral, using InetAddressType and InetAddress.
Connected endpointsCannot be described.Described, with the remote address and port in the index.
Owning programNot reported.Reported by udpEndpointProcess.
IndexLocal address and local port.Local and remote address type, address and port, plus an instance number.

§3The Managed Objects

The scalars of the udp group are counters, all with read-only access: udpInDatagrams at { udp 1 } counts the datagrams delivered to UDP users, udpNoPorts at { udp 2 } counts the received datagrams for which there was no application at the destination port, udpInErrors at { udp 3 } counts the received datagrams that could not be delivered for reasons other than that, and udpOutDatagrams at { udp 4 } counts the datagrams sent from the entity. The two high-capacity counters, udpHCInDatagrams at { udp 8 } and udpHCOutDatagrams at { udp 9 }, are 64-bit counters for devices that can receive or transmit more than 1 million UDP datagrams per second. Discontinuities in any of these counters can occur when the management system is re-initialised, and at other times indicated by discontinuities in sysUpTime.

The udpEndpointTable, at { udp 7 }, holds one row per current UDP endpoint, and a row is identified by seven index columns: udpEndpointLocalAddressType, udpEndpointLocalAddress, udpEndpointLocalPort, udpEndpointRemoteAddressType, udpEndpointRemoteAddress, udpEndpointRemotePort and udpEndpointInstance. The address type in the table is the address type used for the communication, whatever higher-level abstraction the application uses, so an application that uses IPv6 sockets to talk IPv4 between ::ffff:10.0.0.1 and ::ffff:10.0.0.2 still uses unknown(0) value ipv4(1) for the address type. The instance column, whose range starts at 1, distinguishes several processes connected to the same endpoint, which on a system using BSD sockets is what supports the SO_REUSEADDR and SO_REUSEPORT options. The only readable column of the table is udpEndpointProcess, which holds the process identifier of the program associated with the endpoint, or zero when there is no such process.

Implementers are warned about the length of the key. If the total number of elements in udpEndpointLocalAddress and udpEndpointRemoteAddress exceeds 111, the object identifiers of the column instances have more than 128 sub-identifiers and cannot be accessed with SNMPv1, SNMPv2c or SNMPv3, so the table should not hold entries that would produce such identifiers.

The counters are simple totals: datagrams in, datagrams out, datagrams that arrived with nobody listening, and datagrams that could not be handed over. The table is keyed by the local and remote address and port, so each row is one open socket, and the last readable value in the row is the identifier of the program that owns it.

THE COUNTERS THE UDP MIB EXPOSES
  • udpInDatagramsDatagrams delivered to UDP users.
  • udpNoPortsReceived datagrams for which no application was at the destination port.
  • udpInErrorsReceived datagrams that could not be delivered for other reasons.
  • udpOutDatagramsDatagrams sent from this entity.
  • udpHCInDatagramsThe same as udpInDatagrams, as a 64-bit counter for fast links.
  • udpHCOutDatagramsThe same as udpOutDatagrams, as a 64-bit counter for fast links.

§3How a Listening Application Appears

Because the table can describe a socket bound to a remote host, the document sets out how a listening application is represented, in three ways.

  • An application willing to accept both IPv4 and IPv6 datagrams is represented by a udpEndpointLocalAddressType of unknown(0) and a udpEndpointLocalAddress of a zero-length octet string.
  • An application willing to accept only IPv4 or only IPv6 is represented by the appropriate address type and a udpEndpointLocalAddress of '0.0.0.0' or '::' respectively.
  • An application listening for datagrams only for one specific IP address, but from any remote system, is represented by the appropriate address type with udpEndpointLocalAddress set to that local address.

In every case where the remote side is a wildcard, udpEndpointRemoteAddressType is unknown(0), udpEndpointRemoteAddress is a zero-length octet string, and udpEndpointRemotePort is 0. If the operating system demultiplexes UDP packets by remote address and port, or the application has connected its socket by specifying a default remote address and port, the remote values should be filled in to reflect that.

A socket that accepts traffic from anyone is recorded with an empty remote address and port zero. A socket that talks to one fixed host is recorded with that host's address and port. A socket that accepts both IPv4 and IPv6 is recorded with a special address type and an empty local address.

THE COLUMNS OF ONE ENDPOINT ROW
  • Local address type and addressThe address family and address the endpoint is bound to locally.
  • Local portThe port number the endpoint is bound to.
  • Remote address type and addressThe remote family and address, or empty when any remote is accepted.
  • Remote portThe remote port, or zero when any remote is accepted.
  • InstanceDistinguishes several programs connected to the same endpoint.
  • ProcessThe identifier of the program that owns the endpoint, or zero.

§6Security Considerations

No object in this MIB has a read-write or read-create access clause, so if the module is implemented correctly there is no risk that an intruder can alter or create objects of this module with a direct SNMP SET operation.

Some of the readable objects may still be sensitive in some environments, and even reading them should be controlled. The indices of the udpEndpointTable and the udpTable contain information about the listeners on an entity: the udpEndpointLocalPort and udpLocalPort objects in the indices reveal which ports are open on the machine and therefore which attacks are likely to succeed, without the attacker having to run a port scanner.

SNMP versions before SNMPv3 did not include adequate security, and even on a secure network there is no control over who may read or change the objects of this module. The document recommends that implementors use the security features of the SNMPv3 framework, including full support for its cryptographic mechanisms for authentication and privacy, and that deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. It is then the operator's responsibility to configure the SNMP entity so that only principals with legitimate rights can reach these objects.

Everything in this module is read-only, so nobody can change a value through it. Reading is a different matter: the table shows which ports are open, which is a map of the machine for anyone who should not have it. The document therefore asks for SNMPv3 with encryption and authentication, and for access to be limited to the accounts that need it.

§7IANA Considerations

The MIB module uses the object identifier values recorded in the SMI Numbers registry: the udp group of objects sits at { mib-2 7 } and the udpMIB module at { mib-2 50 }. Within the group, the counters occupy { udp 1 } to { udp 4 }, the deprecated IPv4 udpTable is at { udp 5 }, the current udpEndpointTable is at { udp 7 } and the high-capacity counters are at { udp 8 } and { udp 9 }. The value { udp 6 } was the IPv6 table of the IPV6-UDP-MIB in RFC 2454 and is obsoleted by this document.

The module registers two numbers with IANA: the group of UDP objects and the module itself. The counters and tables inside the group have fixed numbers, so a manager can find them without searching.

THE OBJECT IDENTIFIERS THE MODULE ASSIGNS
  • { mib-2 7 }udp — The group of UDP objects.
  • { mib-2 50 }udpMIB — The UDP MIB module.
  • { udp 1 }udpInDatagrams — Datagrams delivered to UDP users.
  • { udp 2 }udpNoPorts — Received datagrams with no application at the destination port.
  • { udp 3 }udpInErrors — Received datagrams that could not be delivered for other reasons.
  • { udp 4 }udpOutDatagrams — Datagrams sent from this entity.
  • { udp 5 }udpTable — The deprecated IPv4 listener table.
  • { udp 7 }udpEndpointTable — The current table of UDP endpoints.
  • { udp 8 }udpHCInDatagrams — High-capacity counter of datagrams delivered to UDP users.
  • { udp 9 }udpHCOutDatagrams — High-capacity counter of datagrams sent from this entity.

§8References