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Title: Hitchhiker's Guide to the Internet

Author: Ed Krol

Posting Date: December 17, 2011 [EBook #39] Release Date: September, 1992

Language: English

*** START OF THIS PROJECT GUTENBERG EBOOK HITCHHIKER'S GUIDE TO THE INTERNET ***

            The Hitchhikers Guide to the Internet
                        25 August 1987

                           Ed Krol
                    [email protected]

 This document was produced through funding of the National
 Science Foundation.

Copyright (C) 1987, by the Board of Trustees of The University of Illinois. Permission to duplicate this document, in whole or part, is granted provided reference is made to the source and this copyright is included in whole copies.

This document assumes that one is familiar with the workings of a non-connected simple IP network (e.g. a few 4.2 BSD systems on an Ethernet not connected to anywhere else). Appendix A contains remedial information to get one to this point. Its purpose is to get that person, familiar with a simple net, versed in the "oral tradition" of the Internet to the point that that net can be connected to the Internet with little danger to either. It is not a tutorial, it consists of pointers to other places, literature, and hints which are not normally documented. Since the Internet is a dynamic environment, changes to this document will be made regularly. The author welcomes comments and suggestions. This is especially true of terms for the glossary (definitions are not necessary).

In the beginning there was the ARPAnet, a wide area experimental network connecting hosts and terminal servers together. Procedures were set up to regulate the allocation of addresses and to create voluntary standards for the network. As local area networks became more pervasive, many hosts became gateways to local networks. A network layer to allow the interoperation of these networks was developed and called IP (Internet Protocol). Over time other groups created long haul IP based networks (NASA, NSF, states…). These nets, too, interoperate because of IP. The collection of all of these interoperating networks is the Internet.

Two groups do much of the research and information work of the Internet (ISI and SRI). ISI (the Informational Sciences Institute) does much of the research, standardization, and allocation work of the Internet. SRI International provides information services for the Internet. In fact, after you are connected to the Internet most of the information in this document can be retrieved from the Network Information Center (NIC) run by SRI.

Operating the Internet

 Each network, be it the ARPAnet, NSFnet or a regional network,
 has its own operations center. The ARPAnet is run by
 BBN, Inc. under contract from DARPA. Their facility is
 called the Network Operations Center or NOC. Cornell
 University temporarily operates NSFnet (called the Network
 Information Service Center, NISC). It goes on to the

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regionals having similar facilities to monitor and keep watch over the goings on of their portion of the Internet. In addition, they all should have some knowledge of what is happening to the Internet in total. If a problem comes up, it is suggested that a campus network liaison should contact the network operator to which he is directly connected. That is, if you are connected to a regional network (which is gatewayed to the NSFnet, which is connected to the ARPAnet…) and have a problem, you should contact your regional network operations center.

RFCs

The internal workings of the Internet are defined by a set of documents called RFCs (Request for Comments). The general process for creating an RFC is for someone wanting something formalized to write a document describing the issue and mailing it to Jon Postel ([email protected]). He acts as a referee for the proposal. It is then commented upon by all those wishing to take part in the discussion (electronically of course). It may go through multiple revisions. Should it be generally accepted as a good idea, it will be assigned a number and filed with the RFCs.

The RFCs can be divided into five groups: required, suggested, directional, informational and obsolete. Required RFC's (e.g. RFC-791, The Internet Protocol) must be implemented on any host connected to the Internet. Suggested RFCs are generally implemented by network hosts. Lack of them does not preclude access to the Internet, but may impact its usability. RFC-793 (Transmission Control Protocol) is a suggested RFC. Directional RFCs were discussed and agreed to, but their application has never come into wide use. This may be due to the lack of wide need for the specific application (RFC-937 The Post Office Protocol) or that, although technically superior, ran against other pervasive approaches (RFC-891 Hello). It is suggested that should the facility be required by a particular site, animplementation be done in accordance with the RFC. This insures that, should the idea be one whose time has come, the implementation will be in accordance with some standard and will be generally usable. Informational RFCs contain factual information about the Internet and its operation (RFC-990, Assigned Numbers). Finally, as the Internet and technology have grown, some RFCs have become unnecessary. These obsolete RFCs cannot be ignored, however. Frequently when a change is made to some RFC that causes a new one to be issued obsoleting others, the new RFC only contains explanations and motivations for the change. Understanding the model on which the whole facility is based may involve reading the original and subsequent RFCs on the topic.

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(Appendix B contains a list of what are considered to be the major RFCs necessary for understanding the Internet).

The Network Information Center

The NIC is a facility available to all Internet users which provides information to the community. There are three means of NIC contact: network, telephone, and mail. The network accesses are the most prevalent. Interactive access is frequently used to do queries of NIC service overviews, look up user and host names, and scan lists of NIC documents. It is available by using

%telnet sri-nic.arpa

on a BSD system and following the directions provided by a user friendly prompter. From poking around in the databases provided one might decide that a document named NETINFO:NUG.DOC (The Users Guide to the ARPAnet) would be worth having. It could be retrieved via an anonymous FTP. An anonymous FTP would proceed something like the following. (The dialogue may vary slightly depending on the implementation of FTP you are using).

      %ftp sri-nic.arpa
      Connected to sri-nic.arpa.
      220 SRI_NIC.ARPA FTP Server Process 5Z(47)-6 at Wed
17-Jun-87 12:00 PDT
      Name (sri-nic.arpa:myname): anonymous
      331 ANONYMOUS user ok, send real ident as password.
      Password: myname
      230 User ANONYMOUS logged in at Wed 17-Jun-87 12:01 PDT,
job 15.
      ftp> get netinfo:nug.doc
      200 Port 18.144 at host 128.174.5.50 accepted.
      150 ASCII retrieve of <NETINFO>NUG.DOC.11 started.
      226 Transfer Completed 157675 (8) bytes transferred
      local: netinfo:nug.doc remote:netinfo:nug.doc
      157675 bytes in 4.5e+02 seconds (0.34 Kbytes/s)
      ftp> quit
      221 QUIT command received. Goodbye.

 (Another good initial document to fetch is
 NETINFO:WHAT-THE-NIC-DOES.TXT)!

 Questions of the NIC or problems with services can be asked
 of or reported to using electronic mail. The following
 addresses can be used:

      [email protected] General user assistance, document requests
      [email protected] User registration and WHOIS updates
      [email protected] Hostname and domain changes and updates
      [email protected] SRI-NIC computer operations
      [email protected] Comments on NIC publications and services

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For people without network access, or if the number of documents is large, many of the NIC documents are available in printed form for a small charge. One frequently ordered document for starting sites is a compendium of major RFCs. Telephone access is used primarily for questions or problems with network access. (See appendix B for mail/telephone contact numbers).

The NSFnet Network Service Center

The NSFnet Network Service Center (NNSC) is funded by NSF to provide a first level of aid to users of NSFnet should they have questions or encounter problems traversing the network. It is run by BBN Inc. Karen Roubicek ([email protected]) is the NNSC user liaison.

The NNSC, which currently has information and documents online and in printed form, plans to distribute news through network mailing lists, bulletins, newsletters, and online reports. The NNSC also maintains a database of contact points and sources of additional information about NSFnet component networks and supercomputer centers.

 Prospective or current users who do not know whom to call
 concerning questions about NSFnet use, should contact the
 NNSC. The NNSC will answer general questions, and, for
 detailed information relating to specific components of the
 Internet, will help users find the appropriate contact for
 further assistance. (Appendix B)

Mail Reflectors

The way most people keep up to date on network news is through subscription to a number of mail reflectors. Mail reflectors are special electronic mailboxes which, when they receive a message, resend it to a list of other mailboxes. This in effect creates a discussion group on a particular topic. Each subscriber sees all the mail forwarded by the reflector, and if one wants to put his "two cents" in sends a message with the comments to the reflector….

The general format to subscribe to a mail list is to find the address reflector and append the string -REQUEST to the mailbox name (not the host name). For example, if you wanted to take part in the mailing list for NSFnet reflected by [email protected], one sends a request to

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[email protected]. This may be a wonderful scheme, but the problem is that you must know the list exists in the first place. It is suggested that, if you are interested, you read the mail from one list (like NSFNET) and you will probably become familiar with the existence of others. A registration service for mail reflectors is provided by the NIC in the files NETINFO:INTEREST-GROUPS-1.TXT, NETINFO:INTEREST-GROUPS-2.TXT, and NETINFO:INTEREST-GROUPS- 3.TXT.

The NSFNET mail reflector is targeted at those people who have a day to day interest in the news of the NSFnet (the backbone, regional network, and Internet inter-connection site workers). The messages are reflected by a central location and are sent as separate messages to each subscriber. This creates hundreds of