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 default query type to host information, with an initial timeout of 10
       seconds, type:

          nslookup -query=hinfo  -timeout=10

       The -version option causes nslookup to print the version number and immediately exit.

INTERACTIVE COMMANDS

       host [server]
              This command looks 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 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 answer
              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 response 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 alternative is not specified.

              norecurse
                     This  keyword  tells  the  name  server  to  query  other  servers  if it does not have the
                     information. The default is recurse; 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 always be used when  sending  requests
                     to the server.  novc is the default.

              nofail This keyword tries the next nameserver if a nameserver responds with SERVFAIL or a referral
                     (nofail), or terminates the query (fail) on such a response. The default is nofail.

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) support, it can  accept  and  display
       non-ASCII  domain  names.  nslookup  appropriately  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 support 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

       2025, Internet Systems Consortium