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RFC 1166

Informational
Pages: 182
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Internet numbers

Part 1 of 8, p. 1 to 7
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Obsoletes:    1117    1062    1020
Updated by:    5737


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Network Working Group                                     S. Kirkpatrick
Request for Comments: 1166                                      M. Stahl
Obsoletes RFCs: 1117, 1020, 997, 990, 960, 943,                M. Recker
943, 923, 900, 870, 820, 790, 776, 770, 762,                   July 1990
758, 755, 750, 739, 604, 503, 433, 349
Obsoletes IENs:  127, 117, 93


                            INTERNET NUMBERS

Status of this Memo

   This memo is a status report on the network numbers and autonomous
   system numbers used in the Internet community.  Distribution of this
   memo is unlimited.

Table of Contents

   Introduction....................................................   1
   Network Numbers.................................................   4
   Class A Networks................................................   7
   Class B Networks................................................   8
   Class C Networks................................................  47
   Other Reserved Internet Addresses............................... 100
   Network Totals.................................................. 101
   Autonomous System Numbers....................................... 102
   Documents....................................................... 111
   Contacts........................................................ 115
   Security Considerations......................................... 182
   Authors' Addresses.............................................. 182

Introduction

   This Network Working Group Request for Comments documents the
   currently assigned network numbers and gateway autonomous systems.
   This RFC will be updated periodically, and in any case current
   information can be obtained from Hostmaster at the DDN Network
   Information Center (NIC).

         Hostmaster
         DDN Network Information Center
         SRI International
         333 Ravenswood Avenue
         Menlo Park, California  94025

         Phone: 1-800-235-3155

         Network mail: HOSTMASTER@NIC.DDN.MIL

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   Most of the protocols used in the Internet are documented in the RFC
   series of notes.  Some of the items listed are undocumented.  Further
   information on protocols can be found in the memo published by the
   Internet Activites Board (IAB), "IAB Official Protocol Standards"
   [52], which describes the state of standardization of protocols used
   in the Internet.  This document is issued quarterly.  Current copies
   may be obtained from the DDN Network Information Center.

   The lists below contain the name and network mailbox of the
   individuals responsible for each registered network or autonomous
   system.  The bracketed entry, e.g. [nn,iii], at the right hand margin
   of the page indicates a reference for the listed network or
   autonomous system, where the number ("nn") cites the document and the
   letters ("iii") cite the NIC Handle of the responsible person.  The
   NIC Handle is a unique identifier that is used in the NIC
   WHOIS/NICNAME service.  People occasionally change electronic
   mailboxes.  To find out the current network mailbox or phone number
   for an individual, or to get information about a registered network,
   use the NIC WHOIS/NICNAME service or contact HOSTMASTER@NIC.DDN.MIL.

   The convention used for the documentation of Internet Protocols is to
   express numbers in decimal and to picture data in "big-endian" order
   [39].  That is, fields are described left to right, with the most
   significant octet on the left and the least significant octet on the
   right.

   The order of transmission of the header and data described in this
   document is resolved to the octet level.  Whenever a diagram shows a
   group of octets, the order of transmission of those octets is the
   normal order in which they are read in English.  For example, in the
   following diagram the octets are transmitted in the order they are
   numbered.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       1       |       2       |       3       |       4       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       5       |       6       |       7       |       8       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       9       |      10       |      11       |      12       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                           Transmission Order of Bytes


   Whenever an octet represents a numeric quantity the left most bit in
   the diagram is the high order or most significant bit.  That is, the

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   bit labeled 0 is the most significant bit.  For example, the
   following diagram represents the value 170 (decimal).

                               0 1 2 3 4 5 6 7
                              +-+-+-+-+-+-+-+-+
                              |1 0 1 0 1 0 1 0|
                              +-+-+-+-+-+-+-+-+

                              Significance of Bits

   Similarly, whenever a multi-octet field represents a numeric quantity
   the left most bit of the whole field is the most significant bit.
   When a multi-octet quantity is transmitted the most significant octet
   is transmitted first.

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NETWORK NUMBERS

   The network numbers listed here are used as internet addresses by the
   Internet Protocol (IP) [14,26].  The IP uses a 32-bit address field
   and divides that address into a network part and a "rest" or local
   address part.  The division takes 4 forms or classes.

      The first type of address, or class A, has a 7-bit network number
      and a 24-bit local address.  The highest-order bit is set to 0.
      This allows 128 class A networks.


                            1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |0|   NETWORK   |                Local Address                  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Class A Address


      The second type of address, class B, has a 14-bit network number
      and a 16-bit local address.  The two highest-order bits are set to
      1-0.  This allows 16,384 class B networks.


                            1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |1 0|           NETWORK         |          Local Address        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Class B Address


      The third type of address, class C, has a 21-bit network number
      and a 8-bit local address.  The three highest-order bits are set
      to 1-1-0.  This allows 2,097,152 class C networks.


                            1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |1 1 0|                    NETWORK              | Local Address |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Class C Address

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      The fourth type of address, class D, is used as a multicast
      address [13].  The four highest-order bits are set to 1-1-1-0.


                            1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |1 1 1 0|                  multicast address                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Class D Address


      Note:  No addresses are allowed with the four highest-order bits
      set to 1-1-1-1.  These addresses, called "class E", are reserved.

   One commonly used notation for internet host addresses divides the
   32-bit address into four 8-bit fields and specifies the value of each
   field as a decimal number with the fields separated by periods.  This
   is called the "dotted decimal" notation.  For example, the internet
   address of VENERA.ISI.EDU in dotted decimal is 128.009.000.032, or
   128.9.0.32.

   The dotted decimal notation will be used in the listing of assigned
   network numbers.  The class A networks will have nnn.rrr.rrr.rrr, the
   class B networks will have nnn.nnn.rrr.rrr, and the class C networks
   will have nnn.nnn.nnn.rrr, where nnn represents part or all of a
   network number and rrr represents part or all of a local address.

   There are four catagories of users of Internet Addresses: Research,
   Defense, Government (Non-Defense), and Commercial.  To reflect the
   allocation of network identifiers among the categories, a one-
   character code is placed to the left of the network number: R for
   Research, D for Defense, G for Government, and C for Commercial (see
   Appendix A for further details on this division of the network
   identification).

   Network numbers are assigned for networks that are connected to the
   research Internet and operational Internet, and for independent
   networks that use the IP family protocols (these are usually
   commercial).  These independent networks are marked with an asterisk
   preceding the number.

   The administrators of independent networks must apply separately for
   permission to interconnect their network with the Internet.
   Independent networks should not be listed in the working tables of
   the Internet hosts or gateways.

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   For various reasons, the assigned numbers of networks are sometimes
   changed.  To ease the transition the old number will be listed for a
   transition period as well.  These "old number" entries will be marked
   with a "T" following the number and preceding the name, and the
   network name will be suffixed "-TEMP".

   Special Addresses:

      In certain contexts, it is useful to have fixed addresses with
      functional significance rather than as identifiers of specific
      hosts.

         The address zero is to be interpreted as meaning "this", as in
         "this network".

            For example, the address 0.0.0.37 could be interpreted as
            meaning host 37 on this network.

         The address of all ones are to be interpreted as meaning "all",
         as in "all hosts".

            For example, the address 128.9.255.255 could be interpreted
            as meaning all hosts on the network 128.9.

         The class A network number 127 is assigned the "loopback"
         function, that is, a datagram sent by a higher level protocol
         to a network 127 address should loop back inside the host.  No
         datagram "sent" to a network 127 address should ever appear on
         any network anywhere.

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Class A Networks

      * Internet Address                   Network           Reference
      - ----------------                   -------           ----------
       *0.rrr.rrr.rrr                      Reserved          [JBP]
        1.rrr.rrr.rrr-2.rrr.rrr.rrr        Unassigned        [NIC]
      C*3.rrr.rrr.rrr                      GE-INTERNET       [JEB50]
      R 4.rrr.rrr.rrr                      SATNET            [SHB]
        5.rrr.rrr.rrr                      Unassigned        [NIC]
      D 6.rrr.rrr.rrr                      YPG-NET           [BWA]
      D 7.rrr.rrr.rrr                      EDN-TEMP          [EC5]
      R 8.rrr.rrr.rrr                      BBNCCNET          [SGC]
      R 9.rrr.rrr.rrr                      IBM               [JP247]
      R 10.rrr.rrr.rrr                     ARPANET           [JS283]
      D 11.rrr.rrr.rrr                     DODIIS            [GEG4]
      C 12.rrr.rrr.rrr                     ATT               [MH82]
      C 13.rrr.rrr.rrr                     XEROX-NET         [SJ33]
      C 14.rrr.rrr.rrr                     PDN               [JKR1]
      R 15.rrr.rrr.rrr                     HP-INTERNET       [WU1]
      C 16.rrr.rrr.rrr                     DEC-INTERNET      [BKR]
        17.rrr.rrr.rrr                     Unassigned        [NIC]
      R 18.rrr.rrr.rrr                     MIT-TEMP          [JIS]
      C*19.rrr.rrr.rrr                     FINET             [RJB3]
      D*20.rrr.rrr.rrr                     ANALYTICS         [BD107]
      D 21.rrr.rrr.rrr                     DDN-RVN           [MLC]
      D*22.rrr.rrr.rrr                     DSNET1            [GEG4]
      D 23.rrr.rrr.rrr                     DDN-TC-NET        [DH17]
        24.rrr.rrr.rrr                     Unassigned        [NIC]
      R 25.rrr.rrr.rrr                     RSRE-EXP          [DBH11]
      D 26.rrr.rrr.rrr                     MILNET            [TMH6]
      R 27.rrr.rrr.rrr                     NOSC-LCCN-TEMP    [RH6]
      R 28.rrr.rrr.rrr                     WIDEBAND          [CJW2]
      D 29.rrr.rrr.rrr                     MILX25-TEMP       [TMH6]
      D 30.rrr.rrr.rrr                     ARPAX25-TEMP      [TMH6]
      G 31.rrr.rrr.rrr                     UCDLA-NET         [CL64]
        32.rrr.rrr.rrr-34.rrr.rrr.rrr      Unassigned        [NIC]
      R 35.rrr.rrr.rrr                     MERIT             [HWB]
      R 36.rrr.rrr.rrr                     SU-NET-TEMP       [VAF]
        37.rrr.rrr.rrr-40.rrr.rrr.rrr      Unassigned        [NIC]
      R 41.rrr.rrr.rrr                     BBN-TEST-A        [RH6]
      R 42.rrr.rrr.rrr                     CAN-INET          [MV38]
      R*43.rrr.rrr.rrr                     JAPAN-A           [JM292]
      R 44.rrr.rrr.rrr                     AMPRNET           [PK28]
        45.rrr.rrr.rrr                     Reserved          [NIC]
      C 46.rrr.rrr.rrr                     BBNET             [JSG1]
      R 47.rrr.rrr.rrr                     BNR               [BM178]
        48.rrr.rrr.rrr-126.rrr.rrr.rrr     Unassigned        [NIC]
       *127.rrr.rrr.rrr                    Loopback          [JBP]


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