RFC 1166
Internet numbers
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
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
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.
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
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.
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.
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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