rfc1739.txt

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Network Working Group                                         G. Kessler
Request for Comments: 1739                                    S. Shepard
Category: Informational                            Hill Associates, Inc.
                                                           December 1994


                 A Primer On Internet and TCP/IP Tools

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.

Table of Contents

   1. Introduction ..................................................  2
   2. A Beginner's Guide to TCP/IP-based Utilities and Applications .  2
   2.1. NSLOOKUP ....................................................  3
   2.2. PING ........................................................  5
   2.3. FINGER ......................................................  6
   2.4. TRACEROUTE ..................................................  7
   2.5. FTP ......................................................... 10
   2.6. TELNET ...................................................... 14
   2.7. User Database Lookup Tools .................................. 17
   2.7.1. WHOIS/NICNAME ............................................. 17
   2.7.2. KNOWBOT ................................................... 20
   2.7.3. NETFIND ................................................... 21
   2.8. Information Servers ......................................... 24
   2.8.1. ARCHIE .................................................... 24
   2.8.2. GOPHER .................................................... 27
   2.8.3. Other Information Servers ................................. 30
   2.9. Uniform Resource Locator Format ............................. 31
   3. Distribution Lists and Mailing Lists .......................... 32
   3.1. Internet Discussion Lists ................................... 33
   3.2. Usenet ...................................................... 33
   3.3. BITNET/EARN ................................................. 35
   4. Internet Documentation ........................................ 36
   4.1. Request for Comments (RFCs) ................................. 36
   4.2. Internet Standards .......................................... 38
   4.3. For Your Information Documents .............................. 39
   4.4. RARE Technical Reports ...................................... 40
   5. Perusing the Internet ......................................... 40
   6. Acronyms and Abbreviations .................................... 42
   7. Security Considerations ....................................... 43
   8. Acknowledgements .............................................. 43
   9. References .................................................... 43
   10. Authors' Addresses ........................................... 46



Kessler & Shepard                                               [Page 1]

RFC 1739           Primer on Internet & TCP/IP Tools       December 1994


1. Introduction

   This memo is an introductory guide to some of the TCP/IP and Internet
   tools and utilities that allow users to access the wide variety of
   information on the network, from determining if a particular host is
   up to viewing a multimedia thesis on foreign policy.  It also
   describes discussion lists accessible from the Internet, ways to
   obtain Internet documents, and resources that help users weave their
   way through the Internet.  This memo may be used as a tutorial for
   individual self-learning, a step-by-step laboratory manual for a
   course, or as the basis for a site's users manual.  It is intended as
   a basic guide only and will refer to other sources for more detailed
   information.

2. A Beginner's Guide to TCP/IP-based Utilities and Applications

   This section provides descriptions and detailed examples of several
   TCP/IP utilities and applications, including actual sessions using
   these utilities (with some extraneous information removed).  Each
   section below describes a single TCP/IP-based tool, it's application,
   and, in some cases, how it works.  The text description is followed
   by an actual sample session.

   The sample dialogues shown below were made using the Multinet TCP/IP
   software for VAX/VMS or DOS versions of FTP Software's PC/TCP.  While
   the examples below can be used as a guide to using and learning about
   the capabilities of these tools, the reader should understand that
   not all of these utilities may be found at all TCP/IP hosts nor in
   all commercial software packages.  Furthermore, the user interface
   for different packages will be different and the actual command line
   may appear differently than shown here; this will be particularly
   true for graphical user interfaces running over Windows, X-Windows,
   OS/2, or Macintosh systems.  The Internet has many exciting things to
   offer but standardized interfaces to the protocols is not yet one of
   them!  This guide will not provide any detail or motivation about the
   Internet Protocol Suite; more information about the TCP/IP protocols
   and related issues may be found in RFC 1180 [18], Comer [22], Feit
   [23], and Kessler [30].

   In the commands shown in the descriptions below, any item appearing
   in square brackets ([]) is optional and the vertical-bar (|) means
   "or"; parameters appearing with no brackets or within curly brackets
   ({}) are mandatory.  In the sample dialogues, most user input is in
   capital letters (only where allowed) and lines containing user input
   are designated with a "**" in the far-left margin.

   AUTHOR'S NOTE: The sample dialogues are easier to read in the
   secondary, Postscript version of this RFC.



Kessler & Shepard                                               [Page 2]

RFC 1739           Primer on Internet & TCP/IP Tools       December 1994


2.1. NSLOOKUP

   NSLOOKUP is the name server lookup program that comes with many
   TCP/IP software packages.  A user can use NSLOOKUP to examine entries
   in the Domain Name System (DNS) database that pertain to a particular
   host or domain; one common use is to determine a host system's IP
   address from its name or the host's name from its IP address.  The
   general form of the command to make a single query is:

        NSLOOKUP  [IP_address | host_name]

   If the program is started without any parameters, the user will be
   prompted for input; the user can enter either an IP address or host
   name at that time, and the program will respond with the name and
   address of the default name sever, the name server actually used to
   resolve each request, and the IP address and host name that was
   queried.  "Exit" is used to quit the NSLOOKUP application.

   Three simple queries are shown in the example below:

  1. Requests the address of the host named "emily.uvm.edu", a system at
     the University of Vermont (UVM).  As it turns out, this is not the
     true name of the host, but a shortened version of the name that is
     accepted as an alias by the network.  The full name of the host and
     the IP address are listed by NSLOOKUP.

  2. Requests the address of host "emily.emba.uvm.edu", which is the
     same host as in the first query.  Note that NSLOOKUP provides a
     "non-authoritative" answer.  Since NSLOOKUP just queried this same
     address, the information is still in its cache memory.  Rather than
     send additional messages to the name server, the answer is one that
     it remembers from before; the server didn't look up the information
     again, however, so it is not guaranteed to still be accurate
     (because the information might have changed within the last few
     milliseconds!).

  3. Requests the name of the host with the given IP address.  The
     result points to the Internet gateway to Australia,
     "munnari.oz.au".

   One additional query is shown in the dialogue below.  NSLOOKUP
   examines information that is stored by the DNS.  The default NSLOOKUP
   queries examine basic address records (called "A records") to
   reconcile the host name and IP address, although other information is
   also available.  In the final query below, for example, the user
   wants to know where electronic mail addressed to the "uvm.edu" domain
   actually gets delivered, since "uvm.edu" is not the name of an actual
   host.  This is accomplished by changing the query type to look for



Kessler & Shepard                                               [Page 3]

RFC 1739           Primer on Internet & TCP/IP Tools       December 1994


   mail exchange (MX) records by issuing a "set type" command (which
   must be in lower case).  The query shows that mail addressed to
   "uvm.edu" is handled though a mail server called "moose.uvm.edu". The
   DNS is beyond the scope of this introduction, although more
   information about the concepts and structure of the DNS can be found
   in STD 13/RFC 1034 [12] and RFC 1591 [13].  The "help" command can be
   issued at the program prompt for information about NSLOOKUP's more
   advanced commands.

   TECHNICAL NOTE: There are other tools that might be available on your
   system or with your software for examining the DNS.  Alternatives to
   NSLOOKUP include HOST and DIG.

      ==================================================================
   ** SMCVAX$ NSLOOKUP

      Default Server:  LOCALHOST
      Address:  127.0.0.1

   ** > EMILY.UVM.EDU
      Server:  LOCALHOST
      Address:  127.0.0.1

      Name:    emily.emba.uvm.edu
      Address:  132.198.1.7
      Aliases:  emily.uvm.edu

   ** > EMILY.EMBA.UVM.EDU
      Server:  LOCALHOST
      Address:  127.0.0.1

      Non-authoritative answer:
      Name:    emily.emba.uvm.edu
      Address:  132.198.1.7

   ** > 128.250.1.21
      Server:  LOCALHOST
      Address:  127.0.0.1

      Name:    munnari.OZ.AU
      Address:  128.250.1.21

   ** > set type=MX
   ** > UVM.EDU
      Server:  LOCALHOST
      Address:  127.0.0.1

      uvm.edu preference = 10, mail exchanger = moose.uvm.edu



Kessler & Shepard                                               [Page 4]

RFC 1739           Primer on Internet & TCP/IP Tools       December 1994


      moose.uvm.edu   internet address = 132.198.101.60

   ** > EXIT

      SMCVAX$
      ==================================================================

2.2. PING

   Ping is one of the most widely available tools bundled with TCP/IP
   software packages.  Ping uses a series of Internet Control Message
   Protocol (ICMP) Echo messages to determine if a remote host is active
   or inactive, and to determine the round-trip delay in communicating
   with it.  The Ping command, referred to as the Packet Internetwork
   Groper in some references, has the following general format:

        PING [-s] {IP_address | host_name} [size] [quantity]

   In the first test below, we ping the host "thumper.bellcore.com" to
   determine whether it is up and running.  This simple use of the
   command contains no optional parameters.

   In the second test, the "-s" parameter tells the system to send an
   ICMP Echo message every second.  The optional "size" parameter
   specifies that each message should be 64 bytes in length (which is
   the default size); the optional "quantity" parameter indicates that
   this test will only send 12 messages (the default is to run the test
   continuously until interrupted).  The results of the second test
   displays the round-trip delay of each Echo message that is returned
   to the sending host; at the end of the test, summary statistics are
   displayed.

      ==================================================================
   ** SMCVAX$ PING THUMPER.BELLCORE.COM
      thumper.bellcore.com is alive

   ** SMCVAX$ PING -S THUMPER.BELLCORE.COM  64  12
      PING THUMPER.BELLCORE.COM (128.96.41.1): 56 data bytes
      64 bytes from 128.96.41.1: icmp_seq=0 time=150 ms
      64 bytes from 128.96.41.1: icmp_seq=1 time=110 ms
      64 bytes from 128.96.41.1: icmp_seq=2 time=130 ms
      64 bytes from 128.96.41.1: icmp_seq=3 time=130 ms
      64 bytes from 128.96.41.1: icmp_seq=4 time=320 ms
      64 bytes from 128.96.41.1: icmp_seq=5 time=110 ms
      64 bytes from 128.96.41.1: icmp_seq=6 time=440 ms
      64 bytes from 128.96.41.1: icmp_seq=7 time=90 ms
      64 bytes from 128.96.41.1: icmp_seq=9 time=100 ms
      64 bytes from 128.96.41.1: icmp_seq=10 time=110 ms



Kessler & Shepard                                               [Page 5]

RFC 1739           Primer on Internet & TCP/IP Tools       December 1994


      ----THUMPER.BELLCORE.COM PING Statistics----
      12 packets transmitted, 10 packets received, 16% packet loss
      round-trip (ms)  min/avg/max = 90/169/440

      SMCVAX$
      ==================================================================

2.3. FINGER

   The Finger program may be used to find out who is logged in on
   another system or to find out detailed information about a specific
   user.  This command has also introduced a brand new verb; "fingering"
   someone on the Internet is not necessarily a rude thing to do!  The
   Finger User Information Protocol is described in RFC 1288 [20].  The
   most general format of the Finger command is:

        FINGER [username]@host_name

   The first example below shows the result of fingering an individual
   user at a remote system.  The first line of the response shows the
   username, the user's real name, their process identifier,
   application, and terminal port number.  Additional information may be
   supplied at the option of the user in "plan" and/or "project" files
   that they supply; these files are often named PLAN.TXT or
   PROJECT.TXT, respectively, and reside in a user's root directory (or
   somewhere in an appropriate search path).

   The second example shows the result of fingering a remote system.
   This lists all of the processes currently running at the fingered
   system or other information, depending upon how the remote system's
   administrator set up the system to respond to the Finger command.