Network Working Group                                       H. Berkowitz
Request for Comments: 1916                             PSC International
Category: Informational                                      P. Ferguson
                                                    cisco Systems, Inc.
                                                              W. Leland
                                                               Bellcore
                                                              P. Nesser
                                             Nesser & Nesser Consulting
                                                          February 1996


   Enterprise Renumbering: Experience and Information Solicitation

Status of this Memo

  This memo provides information for the Internet community.  This memo
  does not specify an Internet standard of any kind.  Distribution of
  this memo is unlimited.

Abstract

  Because of the urgent need for, and substantial difficulty in,
  renumbering IP networks, the PIER working group is compiling a series
  of documents to assist sites in their renumbering efforts.  The
  intent of these documents is to provide both educational and
  practical information to the Internet community. To this end the
  working group is soliciting information from organizations that
  already have gone through, or are in the process of going through,
  renumbering efforts. Case studies, tools, and lists of applications
  that require special attention are sought.

Table of Contents

  1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
  2.   Renumbering Experience . . . . . . . . . . . . . . . . . . . 4
  3.   Information on Tools . . . . . . . . . . . . . . . . . . . . 5
  4.   Application Information  . . . . . . . . . . . . . . . . . . 6
  5.   Security Considerations  . . . . . . . . . . . . . . . . . . 6
  6.   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 7
  A.   Formatting Rules (from RFC 1543) . . . . . . . . . . . . . . 8











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1. Introduction

  There are immediate and increasingly severe requirements to renumber
  both small and large-scale networks. The Procedures for
  Internet/Enterprise Renumbering (PIER) working group in the IETF
  urgently requests specific input for producing concrete guidance for
  the renumbering task as quickly as possible.  As part of collecting
  such information, the PIER working group therefore is soliciting
  input from people and organizations with experience in changing the
  IP addresses of enterprise networks or in making major changes in the
  subnetting of existing networks. We are especially interested in
  actual case studies -- that is, accounts describing what was actually
  done to renumber one or more networks.  Information is also solicited
  on specific tools used in the process, and on areas in which tools
  were needed but not available.  Because applications that use IP
  addresses directly in their configuration or security mechanisms pose
  specific difficulties and coordination issues for renumbering, a
  catalogue of such applications is being compiled.

  All interested parties are invited to submit material in any of these
  areas:

  A) Accounts of the experience of renumbering networks:
  -- Retrospective reports on renumbering efforts.
  -- Journals or running accounts of a renumbering effort, written
     while the task is underway.

  B) Information on tools to help renumbering:
  -- Descriptions of tools used, whether commercial, freeware, or ad
     hoc (such as perl scripts).
  -- Descriptions of specific needs where a tool could clearly have
     helped, but none was found.

  C) Information on applications using embedded IP addresses:
  -- Software applications that use embedded IP addresses for security
     keys, authentication, or any other "inappropriate" purposes.
  -- Hardware devices whose IP addresses are hardcoded into the
     hardware design (and so may require extensive time lags to
     retool).
  -- Both software and hardware whose vendors are no longer in business
     and that may require replacement or specialized solutions.

  The focus of this solicitation is on experience with renumbering that
  has been done or is now underway in IPv4 networks, and not on future
  changes to protocols or environments that may eventually be useful.
  We are especially concerned with the most common situation faced
  today: single-homed networks that are not transit providers. However,
  experience with renumbering more complex environments is also



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  welcome.

  The information provided will be used as an information base from
  which at least three documents will be composed: a document
  summarizing the processes to follow when renumbering, a document
  describing the available tools, and a document containing a list of
  known applications requiring special attention when renumbering. The
  information will also be available on the PIER home page,
  http://www.isi.edu/div7/pier. More specific reports on renumbering
  particular environments may also be produced in those cases where
  enough information is received from the community.

  Although our emphasis is on technical issues and responses, solidly
  based advice on smoothing the human problems is also appreciated.
  Political and cultural sensitivities, and handling them, are major
  issues in the real world.

  There is no requirement that a formal document be submitted, although
  with the permission of the submitter, selected accounts of experience
  in renumbering will be published by PIER as part of their planned
  series of case studies. If you wish to have your account released as
  a PIER case study, please follow the standard RFC format described in
  RFC 1543, "Instructions to RFC Authors". (For convenience, these
  formatting rules are given in Appendix A below.)

  The people and organization(s) involved and the network(s) renumbered
  need not be identified in any document made public by PIER: please
  explicitly indicate if a submission should have its anonymity
  protected.

  The deadline for the submission of your information is May 15, 1996,
  though early submission is encouraged. Any information, however
  informally written, that can be submitted earlier, would be greatly
  appreciated and will help shape the further work of the PIER group.
  In particular, if you expect to submit a detailed write-up by May 15,
  1996, please let us know as soon as possible.

  Please send submissions, questions, or suggestions to the PIER
  discussion list, [email protected].

  To subscribe to the PIER discussion list, please send your request to
  [email protected]. Further information on PIER is available on the
  PIER home page, http://www.isi.edu/div7/pier.

  Mail may also be sent directly to the editors, without its appearing
  on the PIER list, by sending to [email protected].





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2.  Renumbering Experience

  An account of a renumbering effort should provide enough concrete
  information, based on actual experience, so that the reader can
  understand exactly what was done. Broadly speaking, we anticipate two
  styles of account:

  i) Retrospective reports

     Based on one or more renumbering efforts, recapitulate what was
     done and what was learned in the effort. Such a report should
     describe:
     -- The environment being renumbered.
     -- The planning undertaken.
     -- What was done.
     -- What worked.
     -- What didn't (unanticipated issues, problems with planned
        approaches).

     In addition, the report would be even more useful if it also
     addressed:
     -- The reasons for taking the approach chosen.
     -- Any alternative approaches that were rejected, and why.
     -- What could have been done in advance to make the task easier.
     -- Lessons learned: how would you do it next time?

     It is hoped that individuals and organizations that have already
     been through a renumbering effort could quickly look back over
     their experiences, and capture their knowledge.

  ii) Running accounts

     Many people are in the midst of a renumbering effort, or are about
     to embark on one in the next few months. If, in the midst of that
     hectic task, one could write down a brief account or "diary" of
     what actually happens, as it happens, such a report is likely to
     capture the glitches and fixes of even the best-planned effort
     more accurately than any retrospective.

  Of course, these are only rough categories: any record of the
  experience of renumbering or of information gained by such experience
  can be a valuable contribution to PIER. When submitting accounts of
  renumbering efforts, please attempt to be as articulate and concise
  as possible.







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3.  Information on Tools

  Information on the tools that were used in renumbering is valuable,
  whether provided as a separate note or as part of an account of a
  renumbering effort. We welcome comments, however detailed or brief,
  on any tools that helped with renumbering, whether or not you intend
  to produce an account of the entire renumbering effort.

  Some areas in which tools may be used in renumbering include:
  -- Identifying what needs to be changed in your network, such as
     configuration files, hosts and servers with embedded or cached IP
     addresses, DNS, access control lists (ACLs), firewalls, routers,
     license servers, and other applications.
  -- Identifying external factors (such as remote servers, routers, and
     Internet registries) that need to be updated to accommodate your
     new numbers.
  -- Identifying dependencies between the different places where the
     numbers must be updated.
  -- Notifying external agents.
  -- Generating the new information (such as routing, configuration,
     and ACLs) required in order to carry out the updates.
  -- Coordinating updates.
  -- Making the updates.
  -- Verifying the updates.
  -- Trouble-shooting and debugging.
  -- Maintaining network functionality.
  -- Informing your users and other affected human beings (such as NOC
     staff) of the changes.

  The most useful tools are those that are, or can be, available to
  other renumbering efforts. For a given tool, it would be helpful to
  describe:
  -- How to obtain it (if not a well-known tool).
  -- What you used it for.
  -- How you used it.
  -- What its strengths and limitations are for these specific uses.

  If a tool was created as part of the renumbering effort, a
  description of exactly what it does should be included. (For example,
  a script to check for IP addresses in configuration files on user
  machines should be described in terms of just what it did to obtain
  the list of machines, what files it looked for, and how it checked
  them.)

  Although the primary goal of this solicitation is to learn what tools
  exist and are useful, we also value specific, experience-based
  descriptions of ways in which tools could have helped even though
  nothing was available during the renumbering to perform these



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  functions. Advisories on tools that appear to be useful but in
  practice created further problems may also be considered, as
  appropriate.

4.  Application Information

  Information on applications that require special attention when
  renumbering are of particular interest, since specialized
  applications are among the most difficult aspects of renumbering.  It
  typically requires special intervention with the vendor to provide
  new security keys, new license addresses, new versions of
  applications, or perhaps even new hardware or proms to change the
  hardcoded IP addresses.

  A list of any such applications that required "extra" efforts during
  the renumbering process is valuable. Please include as much specific
  information as possible, including but not limited to: application
  name, version, platform, vendor, operating system, operating system
  version, the steps taken to overcome the problem, and lead times
  needed.

  In particular, any applications that are no longer supported, or
  whose vendor has ceased to do business, are extremely important since
  these applications will likely be some of the more difficult issues a
  renumbering effort will encounter.  Any solutions to these types of
  problems, including replacement applications and proprietary
  solutions, are also sought.

5.  Security Considerations

  This RFC raises no security issues, although accounts of renumbering
  are encouraged to describe any security issues encountered, any tools
  that helped identify or resolve the issues, and the actions taken to
  address them. Submissions should give serious consideration to the
  content and context of issues regarding security.
















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6.  Authors' Addresses

  Howard C. Berkowitz
  PSC International
  8260 Greensboro Drive, Suite 330
  McLean, VA 22102

  Phone: (703) 998-5819
  Fax: (703) 998-5058
  EMail: [email protected]


  Paul Ferguson
  cisco Systems, Inc.
  1835 Alexander Bell Drive
  Suite 100
  Reston, VA 22091

  Phone: (703) 716-9538
  Fax: (703) 716-9538
  EMail: [email protected]


  Will E. Leland
  Room 1A-228B
  Bellcore
  445 South Street
  Morristown, NJ 07960-6438

  Phone: (201) 829-4376
  Fax: (201) 829-2504
  EMail: [email protected]


  Philip J. Nesser II
  Nesser & Nesser Consulting
  16015 84th Ave. NE
  Bothell, WA 98011

  Phone: (206) 488-6268
  EMail: [email protected]










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Appendix  A - Formatting Rules (from RFC 1543)

  Note: there are a set of NROFF formatting macros for the following
  format.  Please contact [email protected] if you would like
  to get a copy.

3a.  ASCII Format Rules

  The character codes are ASCII.

  Each page must be limited to 58 lines followed by a form feed on a
  line by itself.

  Each line must be limited to 72 characters followed by carriage
  return and line feed.

  No overstriking (or underlining) is allowed.

  These "height" and "width" constraints include any headers, footers,
  page numbers, or left side indenting.

  Do not fill the text with extra spaces to provide a straight right
  margin.

  Do not do hyphenation of words at the right margin.

  Do not use footnotes.  If such notes are necessary, put them at the
  end of a section, or at the end of the document.

  Use single spaced text within a paragraph, and one blank line between
  paragraphs.

  Note that the number of pages in a document and the page numbers on
  which various sections fall will likely change with reformatting.
  Thus cross references in the text by section number usually are
  easier to keep consistent than cross references by page number.















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