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       nslookup - query Internet name servers interactively


       nslookup [-option] [name | -] [server]


       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.


       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.


       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.

                     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.

                     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.

                     This keyword sets the search list to name.

                     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.

                     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

                     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.

                     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.

                     This  keyword  sets  the  number of dots (label separators) in a domain that
                     disables searching. Absolute names always stop searching.

                     This keyword sets the number of retries to 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.


       nslookup returns with an exit status of 1 if any query failed, and 0 otherwise.


       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.




       dig(1), host(1), named(8).


       Internet Systems Consortium


       2022, Internet Systems Consortium