nslookup - query Internet name servers interactively
nslookup [-option] [name | -]
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 is
used to print just the name and requested information for a host or domain.
Interactive mode is entered in the following cases:
1.when no arguments are given (the default name server
will be used)
2.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
default query type to host information, and the initial timeout to 10
nslookup -query=hinfo -timeout=10
The -version option causes nslookup to print the
version number and immediately exits.
Look up information for host using the current default
server or using server, if specified. If host is an Internet 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 period, the search list is used to qualify the
To look up a host not in the current domain, append a period to
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.
Exits the program.
nslookup returns with an exit status of 1 if any query failed, and 0
If nslookup has been built with IDN (internationalized domain name)
support, it can accept and display non-ASCII domain names. nslookup
appropriately converts character encoding of domain name before sending a
request to DNS server or displaying a reply from the server. If you'd like to
turn off the IDN support for some reason, define the IDN_DISABLE
environment variable. The IDN support is disabled if the variable is set when
nslookup runs or when the standard output is not a tty.
Internet Systems Consortium, Inc.
Copyright © 2004-2007, 2010, 2013-2019 Internet Systems Consortium, Inc.
This command is used to change state information that
affects the lookups. Valid keywords are:
Prints the current values of the frequently used options
to set. Information about the current default server and host is also
Change the query class to one of:
the Internet class
the Chaos class
the Hesiod class
The class specifies the protocol group of the information.
(Default = IN; abbreviation = cl)
Turn on or off the display of the full response packet
and any intermediate response packets when searching.
(Default = nodebug; abbreviation = [no]deb)
Turn debugging mode on or off. This displays more about
what nslookup is doing.
(Default = nod2)
Sets the search list to name.
If the lookup request contains at least one period but
doesn't end with a trailing period, append the domain names in the domain
search list to the request until an answer is received.
(Default = search)
Change the default TCP/UDP name server port to
(Default = 53; abbreviation = po)
Change the type of the information query.
(Default = A; abbreviations = q, ty)
Tell the name server to query other servers if it does
not have the information.
(Default = recurse; abbreviation = [no]rec)
Set the number of dots (label separators) in a domain
that will disable searching. Absolute names always stop searching.
Set the number of retries to number.
Change the initial timeout interval for waiting for a
reply to number seconds.
Always use a virtual circuit when sending requests to the
(Default = novc)
Try the next nameserver if a nameserver responds with
SERVFAIL or a referral (nofail) or terminate query (fail) on such a response.
(Default = nofail)