RFC 2151 (rfc2151) - Page 3 of 52
A Primer On Internet and TCP/IP Tools and Utilities
Alternative Format: Original Text Document
RFC 2151 Internet & TCP/IP Tools & Utilities June 1997
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
Kessler & Shepard Informational