nslookup

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 in‐
   formation 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  ad‐
   dress 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 au‐
          thoritative 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  re‐
                 quest 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 dis‐
   abled if the variable is set when nslookup runs, or when the standard output is not a tty.

FILES

   /etc/resolv.conf