nslookup(1M) nslookup(1M)
NAME
nslookup - query name servers interactively
SYNOPSIS
nslookup [-option ... ] [host-to-find] | - [server]
DESCRIPTION
The nslookup command queries DARPA Internet domain name
servers.
Files
/etc/resolv.conf initial domain name and name
server addresses
/usr/lib/nslookup.help summary of commands
Diagnostics
If the lookup request was not successful, an error message is
printed. Possible errors are:
time-out The server did not respond to a
request after a certain amount
of time (changed with set
timeout=value) and a certain
number of retries (changed with
set retry=value).
no information Depending on the query type set
with the set querytype command,
no information about the host
was available, though the host
name is valid.
non-existent domain The host or domain name does not
exist.
connection refused
network is unreachable The connection to the name or
finger server could not be made
at the current time. This error
commonly occurs with finger
requests.
server failure The name server found an
internal inconsistency in its
database and could not return a
Copyright 1994 Novell, Inc. Page 1
nslookup(1M) nslookup(1M)
valid answer.
refused The name server refused to
service the request.
The following error should not occur and it indicates a bug in
the program.
format error The name server found that the
request packet was not in the
proper format.
USAGE
nslookup has two modes: interactive and non-interactive.
Interactive mode allows the user to query the name server for
information about various hosts and domains or print a list of
hosts in the domain. Non-interactive mode is used to print
just the name and Internet address of a host or domain.
Interactive mode is entered in the following cases:
when no arguments are given (the default name server
will be used), and
when the first argument is a hyphen (-) and the second
argument is the hostname or Internet address of a name
server.
Non-interactive mode is used when the name of the host to be
looked up is given as the first argument. The optional second
argument specifies a name server.
The options listed under the set command below can be
specified on the command line if they precede the arguments
and are prefixed with a hyphen. For example, to change the
default query type to host information, and the default
timeout to 10 seconds, type:
nslookup -query=hinfo -timeout=10
Commands
Commands may be interrupted at any time by typing an interrupt
character (usually CTRL-C). To exit, type a EOF character
(usually CTRL-D). The command line length must be less than
80 characters.
Copyright 1994 Novell, Inc. Page 2
nslookup(1M) nslookup(1M)
host [server]
Look up information for host using the current
default server or using server if it is specified.
server domain
lserver domain
Change the default server to domain. Lserver uses
the initial server to look up information about
domain while server uses the current default server.
If an authoritative answer can't be found, the names
of servers that might have the answer are returned.
root Change the default server to the server for the root
of the domain name space. Currently, the host
ns.nic.ddn.mil is used. (This command is a synonym
for the lserver ns.nic.ddn.mil.) The name of the
root server can be changed with the set root
command.
finger [name] [> filename]
finger [name] [>> filename]
Connects with the finger server on the current host.
The current host is defined when a previous lookup
for a host was successful and returned address
information (see the set querytype=A command). name
is optional. > and >> can be used to redirect
output in the usual manner.
ls domain [> filename]
ls domain [>> filename]
ls -a domain [> filename]
ls -a domain [>> filename]
ls -h domain [> filename]
ls -h domain [>> filename]
ls -d domain [> filename]
List the information available for domain,
optionally creating or appending to filename. The
default output contains host names and their
Copyright 1994 Novell, Inc. Page 3
nslookup(1M) nslookup(1M)
Internet addresses. The -a option lists aliases of
hosts in the domain. The -h option lists CPU and
operating system information for the domain. The -d
option lists all contents of a zone transfer. When
output is directed to a file, hash marks are printed
for every 50 records received from the server.
view filename
Sorts and lists the output of previous ls command(s)
with more(1).
help
? Prints a brief summary of commands.
exit Exits the program.
set keyword[=value]
This command is used to change state information
that affects the lookups. Valid keywords are:
all Prints the current values of the
various options to set. Information
about the current default server and
host is also printed.
class=name Set query class to one of IN
(Internet), CHAOS, HESIOD, or ANY.
Default is IN.
[no]debug Turn debugging mode on. A lot more
information is printed about the
packet sent to the server and the
resulting answer. Default is
nodebug; abbreviation is [no]deb.
[no]d2 Turn exhaustive debugging mode on.
Essentially all fields of every
packet are printed. Default is nod2.
[no]defname Append the default domain name to
every lookup. Default is defname;
abbreviation is [no]def).
Copyright 1994 Novell, Inc. Page 4
nslookup(1M) nslookup(1M)
[no]search With defname, search for each name in
parent domains of the current domain.
Default is search.
domain=name Change the default domain name to
name. The default domain name is
appended to all lookup requests if
the defname option has been set. The
search list is set to parents of the
domain with at least two components
in their names. Default is value in
hostname or /etc/resolv.conf;
abbreviation is do.
[no]ignore Ignore truncate error. Default is
noignore
port=port# Connect to name server using port#.
Default is well known port number)
srchlist=domain
Set search list to domain.
querytype=value
type=value Change the type of information
returned from a query to one of:
A the host's Internet address (the
default)
CNAME the canonical name for an alias
HINFO the host CPU and operating
system type
MD the mail destination
MX the mail exchanger
MG the mail group member
MINFO the mailbox or mail list
information
Copyright 1994 Novell, Inc. Page 5
nslookup(1M) nslookup(1M)
MR the mail rename domain name
NS nameserver for the named zone
Other types specified in the RFC 1035
document are valid but aren't very useful.
Abbreviation is q.
[no]recurse
Tell the name server to query other
servers if it does not have the
information. Default is recurse;
abbreviation is [no]rec.
retry=number
Set the number of retries to number. When
a reply to a request is not received
within a certain amount of time (changed
with set timeout), the request is resent.
The retry value controls how many times a
request is resent before giving up.
Default is 2; abbreviation is ret.
root=host Change the name of the root server to
host. This affects the root command.
Default is ns.nic.ddn.mil; abbreviation is
ro.
timeout=number
Change the time-out interval for waiting
for a reply to number seconds. Default is
10 seconds; abbreviation is t.
[no]vc Always use a virtual circuit when sending
requests to the server. Default is novc;
abbreviation is [no]v.
REFERENCES
named(1M), resolver(3N)
RFC 1034, RFC 1035
Copyright 1994 Novell, Inc. Page 6