rfc2151.txt

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Network Working Group                                         G. Kessler
Request for Comments: 2151                                    S. Shepard
FYI: 30                                            Hill Associates, Inc.
Obsoletes: RFC 1739                                            June 1997
Category: Informational


          A Primer On Internet and TCP/IP Tools and Utilities

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

   This memo is an introductory guide to many of the most commonly-
   available TCP/IP and Internet tools and utilities. It also describes
   discussion lists accessible from the Internet, ways to obtain
   Internet and TCP/IP documents, and some resources that help users
   weave their way through the Internet.

Table of Contents

   1. Introduction...................................................  2
   2. Nomenclature...................................................  2
   3. Finding Information About Internet Hosts and Domains...........  3
      3.1. NSLOOKUP..................................................  3
      3.2. Ping......................................................  6
      3.3. Finger....................................................  8
      3.4. Traceroute................................................  9
   4. The Two Fundamental Tools...................................... 12
      4.1. TELNET.................................................... 12
      4.2. FTP....................................................... 15
   5. User Database Lookup Tools..................................... 19
      5.1. WHOIS/NICNAME............................................. 19
      5.2. KNOWBOT................................................... 23
   6. Information Servers............................................ 24
      6.1. Archie.................................................... 24
      6.2. Gopher.................................................... 28
      6.3. VERONICA, JUGHEAD, and WAIS............................... 30
   7. The World Wide Web............................................. 31
      7.1. Uniform Resource Locators................................. 34
      7.2. User Directories on the Web............................... 35
      7.3. Other Service Accessible Via the Web...................... 36
   8. Discussion Lists and Newsgroups................................ 37
      8.1. Internet Discussion Lists................................. 37



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      8.2. LISTSERV.................................................. 38
      8.3. Majordomo................................................. 38
      8.4. Usenet.................................................... 39
      8.5 Finding Discussion Lists and Newsgroups.................... 40
   9. Internet Documentation......................................... 41
      9.1. Request for Comments (RFCs)............................... 41
      9.2. Internet Standards........................................ 44
      9.3. For Your Information Documents............................ 45
      9.4. Best Current Practices.................................... 45
      9.5. RARE Technical Reports.................................... 46
   10. Perusing the Internet......................................... 46
   11. Acronyms and Abbreviations.................................... 48
   12. Security Considerations....................................... 49
   13. Acknowledgments............................................... 49
   14. References.................................................... 49
   15. Authors' Address.............................................. 51

1. Introduction

   This memo is an introductory guide to some of the most commonly-
   available 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 and TCP/IP documents, and some
   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. Nomenclature

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

   The sample dialogues shown below were obtained from a variety of
   software and hardware systems, including AIX running on an IBM
   RS/6000, Linux on an Intel 486, Multinet TCP/IP over VMS on a VAX,
   and FTP Software's OnNet (formerly PC/TCP) running on a DOS/Windows
   PC. While the examples below can be used as a guide to using and
   learning about the capabilities of TCP/IP 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



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   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. Windows-based sessions are not
   shown in this RFC because of the desire to have a text version of
   this document; in addition, most GUI-based TCP/IP packages obscure
   some of the detail that is essential for understanding what is really
   happening when you click on a button or drag a file. 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 [29], Comer [6], Feit [7], Kessler [14], and
   Stevens [30].

   In the descriptions below, commands are shown in a Courier font
   (Postscript and HTML versions); items appearing in square brackets
   ([]) are optional, the vertical-bar (|) means "or," parameters
   appearing with no brackets or within curly brackets ({}) are
   mandatory, and parameter names that need to be replaced with a
   specific value will be shown in italics (Postscript and HTML
   versions) or within angle brackets (<>, text version). In the sample
   dialogues, user input is in bold (Postscript and HTML versions) or
   denoted with asterisks (**) in the margin (text version).

3. Finding Information About Internet Hosts and Domains

   There are several tools that let you learn information about Internet
   hosts and domains. These tools provide the ability for an application
   or a user to perform host name/address reconciliation (NSLOOKUP),
   determine whether another host is up and available (PING), learn
   about another host's users (Finger), and learn the route that packets
   will take to another host (Traceroute).

3.1. 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



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   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 www.hill.com, the World
      Wide Web server at Hill Associates. As it turns out, this is not
      the true name of the host, but an alias. The full name of the host
      and the IP address are listed by NSLOOKUP.

      2 Requests the address of host syrup.hill.com, 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 hill.com domain
   actually gets delivered, since hill.com is not the true name of an
   actual host. This is accomplished by changing the query type to look
   for mail exchange (MX) records by issuing a set type command (which
   must be in lower case). The query shows that mail addressed to
   hill.com is actually sent to a mail server called mail.hill.com. If
   that system is not available, mail delivery will be attempted to
   first mailme.hill.com and then to netcomsv.netcom.com; the order of
   these attempts is controlled by the "preference" value. This query
   also returns the name of the domain's name servers and all associated
   IP addresses.

   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 [19], RFC 1591 [21], and Kessler [16]. The help
   command can be issued at the program prompt for information about
   NSLOOKUP's more advanced commands.





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   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:  ns1.ner.bbnplanet.net
  Address:  192.52.71.5

**> www.hill.com
  Name:    syrup.hill.com
  Address:  199.182.20.3
  Aliases:  www.hill.com

**> syrup.hill.com
  Non-authoritative answer:
  Name:    syrup.hill.com
  Address:  199.182.20.3

**> 128.250.1.21
  Name:    munnari.OZ.AU
  Address:  128.250.1.21

**> set type=MX
**> hill.com
  hill.com  preference = 20, mail exchanger = mail.hill.com
  hill.com  preference = 40, mail exchanger = mailme.hill.com
  hill.com  preference = 60, mail exchanger = netcomsv.netcom.com
  hill.com  nameserver = nameme.hill.com
  hill.com  nameserver = ns1.noc.netcom.net
  hill.com  nameserver = ns.netcom.com
  mail.hill.com  internet address = 199.182.20.4
  mailme.hill.com     internet address = 199.182.20.3
  netcomsv.netcom.com internet address = 192.100.81.101
  ns1.noc.netcom.net  internet address = 204.31.1.1
  ns.netcom.com  internet address = 192.100.81.105

**> exit
  SMCVAX$
  ====================================================================










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3.2. Ping

   Ping, reportedly an acronym for the Packet Internetwork Groper, is
   one of the most widely available tools bundled with TCP/IP software
   packages.  Ping uses a series of Internet Control Message Protocol
   (ICMP) [22] Echo messages to determine if a remote host is active or
   inactive, and to determine the round-trip delay in communicating with
   it.

   A common form of the Ping command, showing some of the more commonly
   available options that are of use to general users, is:

      ping [-q] [-v] [-R] [-c Count] [-i Wait] [-s PacketSize] Host

   where:

         -q          Quiet output; nothing is displayed except summary
         lines at startup and completion

         -v          Verbose output, which lists ICMP packets that are
         received in addition to Echo Responses

         -R          Record route option; includes the RECORD_ROUTE
         option in the Echo Request packet and displays the route buffer
         on returned packets

         -c Count    Specifies the number of Echo Requests to be sent
         before concluding test (default is to run until interrupted
         with a control-C)

         -i Wait     Indicates the number of seconds to wait between
         sending each packet (default = 1)

         -s PacketSize    Specifies the number of data bytes to be sent;
         the total ICMP packet size will be PacketSize+8 bytes due to
         the ICMP header (default = 56, or a 64 byte packet)

         Host   IP address or host name of target system

   In the first example below, the user pings the host
   thumper.bellcore.com, requesting that 6 (-c) messages be sent, each
   containing 64 bytes (-s) of user data. The display shows the round-
   trip delay of each Echo message returned to the sending host; at the
   end of the test, summary statistics are displayed.