NSLOOKUP(1) BIND 9 NSLOOKUP(1)
NAME
nslookup - query Internet name servers interactively
SYNOPSIS
nslookup [-option] [name | -] [server]
DESCRIPTION
nslookup is a program to query Internet domain name servers. nslookup
has two modes: interactive and non-interactive. Interactive mode allows
the user to query name servers for information about various hosts and
domains or to print a list of hosts in a domain. Non-interactive mode
prints just the name and requested information for a host or domain.
ARGUMENTS
Interactive mode is entered in the following cases:
a. when no arguments are given (the default name server is used);
b. when the first argument is a hyphen (-) and the second argument is
the host name or Internet address of a name server.
Non-interactive mode is used when the name or Internet address of the
host to be looked up is given as the first argument. The optional second
argument specifies the host name or address of a name server.
Options can also be specified on the command line if they precede the
arguments and are prefixed with a hyphen. For example, to change the de‐
fault query type to host information, with an initial timeout of 10 sec‐
onds, type:
nslookup -query=hinfo -timeout=10
The -version option causes nslookup to print the version number and im‐
mediately exit.
INTERACTIVE COMMANDS
host [server]
This command looks up information for host using the current de‐
fault server or using server, if specified. If host is an Inter‐
net address and the query type is A or PTR, the name of the host
is returned. If host is a name and does not have a trailing pe‐
riod (.), the search list is used to qualify the name.
To look up a host not in the current domain, append a period to
the name.
server domain | lserver domain
These commands 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 an‐
swer cannot be found, the names of servers that might have the
answer are returned.
root This command is not implemented.
finger This command is not implemented.
ls This command is not implemented.
view This command is not implemented.
help This command is not implemented.
? This command is not implemented.
exit This command exits the program.
set keyword[=value]
This command is used to change state information that affects the
lookups. Valid keywords are:
all This keyword prints the current values of the frequently
used options to set. Information about the current default
server and host is also printed.
class=value
This keyword changes the query class to one of:
IN the Internet class
CH the Chaos class
HS the Hesiod class
ANY wildcard
The class specifies the protocol group of the information.
The default is IN; the abbreviation for this keyword is
cl.
nodebug
This keyword turns on or off the display of the full re‐
sponse packet, and any intermediate response packets, when
searching. The default for this keyword is nodebug; the
abbreviation for this keyword is [no]deb.
nod2 This keyword turns debugging mode on or off. This displays
more about what nslookup is doing. The default is nod2.
domain=name
This keyword sets the search list to name.
nosearch
If the lookup request contains at least one period, but
does not end with a trailing period, this keyword appends
the domain names in the domain search list to the request
until an answer is received. The default is search.
port=value
This keyword changes the default TCP/UDP name server port
to value from its default, port 53. The abbreviation for
this keyword is po.
querytype=value | type=value
This keyword changes the type of the information query to
value. The defaults are A and then AAAA; the abbreviations
for these keywords are q and ty.
Please note that it is only possible to specify one query
type. Only the default behavior looks up both when an al‐
ternative is not specified.
norecurse
This keyword tells the name server to query other servers
if it does not have the information. The default is re‐
curse; the abbreviation for this keyword is [no]rec.
ndots=number
This keyword sets the number of dots (label separators) in
a domain that disables searching. Absolute names always
stop searching.
retry=number
This keyword sets the number of retries to number.
timeout=number
This keyword changes the initial timeout interval to wait
for a reply to number, in seconds.
novc This keyword indicates that a virtual circuit should al‐
ways be used when sending requests to the server. novc is
the default.
nofail This keyword tries the next nameserver if a nameserver re‐
sponds with SERVFAIL or a referral (nofail), or terminates
the query (fail) on such a response. The default is no‐
fail.
RETURN VALUES
nslookup returns with an exit status of 1 if any query failed, and 0
otherwise.
IDN SUPPORT
If nslookup has been built with IDN (internationalized domain name) sup‐
port, it can accept and display non-ASCII domain names. nslookup appro‐
priately converts character encoding of a domain name before sending a
request to a DNS server or displaying a reply from the server. To turn
off IDN support, define the IDN_DISABLE environment variable. IDN sup‐
port is disabled if the variable is set when nslookup runs, or when the
standard output is not a tty.
FILES
/etc/resolv.conf
SEE ALSO
dig(1), host(1), named(8).
AUTHOR
Internet Systems Consortium
COPYRIGHT
2024, Internet Systems Consortium
9.18.18‐0ubuntu2.1‐Ubuntu 2023‐08‐04 NSLOOKUP(1)