Text 7131, 120 rader
Skriven 1999-10-25 16:05:18 av Mikael Ståldal (2:204/254.337)
   Kommentar till text 6975 av Sigvard Lingh (2:206/145.21)
Ärende: Har det något med saken att göra?
=========================================
SL>>> Jag har inte 127-temat. Jag har konfigurerat mina datorer på
SL>>> 10.0.0.x

SL> Det finns en till serie. Är det 192.168.. någonting?

Favorit i repris:


Network Working Group                                         Y. Rekhter
Request for Comments: 1918                                 Cisco Systems
Obsoletes: 1627, 1597                                       B. Moskowitz BCP: 5
                                                   Chrysler Corp. Category:
Best Current Practice                            D. Karrenberg                 
                                               RIPE NCC
                                                          G. J. de Groot
                                                                RIPE NCC
                                                                 E. Lear
                                                  Silicon Graphics, Inc.
                                                           February 1996


                Address Allocation for Private Internets

Status of this Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

1. Introduction

   For the purposes of this document, an enterprise is an entity
   autonomously operating a network using TCP/IP and in particular
   determining the addressing plan and address assignments within that
   network.

   This document describes address allocation for private internets. The
   allocation permits full network layer connectivity among all hosts
   inside an enterprise as well as among all public hosts of different
   enterprises. The cost of using private internet address space is the
   potentially costly effort to renumber hosts and networks between
   public and private.


[...]


3. Private Address Space

   The Internet Assigned Numbers Authority (IANA) has reserved the
   following three blocks of the IP address space for private internets:

     10.0.0.0        -   10.255.255.255  (10/8 prefix)
     172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
     192.168.0.0     -   192.168.255.255 (192.168/16 prefix)

   We will refer to the first block as "24-bit block", the second as
   "20-bit block", and to the third as "16-bit" block. Note that (in
   pre-CIDR notation) the first block is nothing but a single class A
   network number, while the second block is a set of 16 contiguous
   class B network numbers, and third block is a set of 256 contiguous
   class C network numbers.

   An enterprise that decides to use IP addresses out of the address
   space defined in this document can do so without any coordination
   with IANA or an Internet registry. The address space can thus be used
   by many enterprises. Addresses within this private address space will
   only be unique within the enterprise, or the set of enterprises which
   choose to cooperate over this space so they may communicate with each
   other in their own private internet.

   As before, any enterprise that needs globally unique address space is
   required to obtain such addresses from an Internet registry. An
   enterprise that requests IP addresses for its external connectivity
   will never be assigned addresses from the blocks defined above.

   In order to use private address space, an enterprise needs to
   determine which hosts do not need to have network layer connectivity
   outside the enterprise in the foreseeable future and thus could be
   classified as private. Such hosts will use the private address space
   defined above.  Private hosts can communicate with all other hosts
   inside the enterprise, both public and private. However, they cannot
   have IP connectivity to any host outside of the enterprise. While not
   having external (outside of the enterprise) IP connectivity private
   hosts can still have access to external services via mediating
   gateways (e.g., application layer gateways).

   All other hosts will be public and will use globally unique address
   space assigned by an Internet Registry. Public hosts can communicate
   with other hosts inside the enterprise both public and private and
   can have IP connectivity to public hosts outside the enterprise.
   Public hosts do not have connectivity to private hosts of other
   enterprises.

   Moving a host from private to public or vice versa involves a change
   of IP address, changes to the appropriate DNS entries, and changes to
   configuration files on other hosts that reference the host by IP
   address.

   Because private addresses have no global meaning, routing information
   about private networks shall not be propagated on inter-enterprise
   links, and packets with private source or destination addresses
   should not be forwarded across such links. Routers in networks not
   using private address space, especially those of Internet service
   providers, are expected to be configured to reject (filter out)
   routing information about private networks. If such a router receives
   such information the rejection shall not be treated as a routing
   protocol error.

   Indirect references to such addresses should be contained within the
   enterprise. Prominent examples of such references are DNS Resource
   Records and other information referring to internal private
   addresses. In particular, Internet service providers should take
   measures to prevent such leakage.


[...]

--- Msged/2 4.00
 * Origin: The Perceptible Society (2:204/254.337)