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NSLOOKUP(8)									      NSLOOKUP(8)

NAME
       nslookup - query Internet name servers interactively

SYNOPSIS
       nslookup [ -option ...  ] [ host-to-find | - [ 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 is used to print 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 will be 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.

       The options listed under the ``set'' command below can be  specified  in  the  .nslookuprc
       file  in  the  user's  home directory if they are listed one per line. 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 seconds, type:
	    nslookup -query=hinfo  -timeout=10

INTERACTIVE COMMANDS
       Commands may be interrupted at any time by typing a control-C.  To exit, type a	control-D
       (EOF) or type exit.  The command line length must be less than 256 characters.  To treat a
       built-in command as a host name, precede it with an escape character (\).  N.B. an  unrec-
       ognized command will be interpreted as a host name.

       host [server]
	      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 default domain name is appended to the name.	(This  behavior  depends  on  the
	      state of the set options domain, srchlist, defname, and search).	To look up a host
	      not in the current domain, append a period to the name.

       server domain
       lserver domain
	      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.

       root   Changes  the  default  server  to the server for the root of the domain name space.
	      Currently, the host ns.internic.net is  used.   (This  command  is  a  synonym  for
	      lserver  ns.internic.net.)  The name of the root server can be changed with the set
	      root command.

       finger [name] [> filename]
       finger [name] [>> filename]
	      Connects with the finger server on the current host.  The current host  is  defined
	      when  a  previous lookup for a host was successful and returned address information
	      (see the set querytype=A command).  Name is optional.  > and >> can be used to  re-
	      direct output in the usual manner.

       ls [option] domain [> filename]
       ls [option] domain [>> filename]
	      List  the  information  available  for  domain, optionally creating or appending to
	      filename.  The default output contains host names  and  their  Internet  addresses.
	      Option can be one of the following:

	      -t querytype
		  lists all records of the specified type (see querytype below).

	      -a  lists aliases of hosts in the domain.  synonym for -t  CNAME.

	      -d  lists all records for the domain.  synonym for -t  ANY.

	      -h  lists  CPU  and  operating  system  information  for	the  domain.  synonym for
		  -t  HINFO.

	      -s  lists well-known services of hosts in the domain.  synonym for -t  WKS.

	      When output is directed to a file, hash marks are  printed  for  every  50  records
	      received from the server.

       view filename
	      Sorts and lists the output of previous ls command(s) with more(1).

       help

       ?      Prints a brief summary of commands.

       exit   Exits the program.

       set keyword[=value]
	      This  command  is used to change state information that affects the lookups.  Valid
	      keywords are:

	      all    Prints the current values of the frequently-used options to  set.	 Informa-
		     tion about the  current default server and host is also printed.

	      class=value
		     Change the query class to one of:

		     IN        the Internet class.

		     CHAOS     the Chaos class.

		     HESIOD    the MIT Athena Hesiod class.

		     ANY       wildcard (any of the above).

		     The class specifies the protocol group of the information.
		     (Default = IN, abbreviation = cl)

	      [no]debug
		     Turn  debugging  mode on. A lot more information is printed about the packet
		     sent to the server and the resulting answer.
		     (Default = nodebug, abbreviation = [no]deb)

	      [no]d2 Turn exhaustive debugging mode on.  Essentially all fields of  every  packet
		     are printed.
		     (Default = nod2)

	      domain=name
		     Change the default domain name to name.  The default domain name is appended
		     to a lookup request depending  on	the  state  of	the  defname  and  search
		     options.	The domain search list contains the parents of the default domain
		     if it has at least two components in its name.  For example, if the  default
		     domain  is  CC.Berkeley.EDU,  the	search list is CC.Berkeley.EDU and Berke-
		     ley.EDU.  Use the set srchlist command to specify a different list.  Use the
		     set all command to display the list.
		     (Default  =  value from hostname, /etc/resolv.conf or LOCALDOMAIN, abbrevia-
		     tion = do)

	      srchlist=name1/name2/...
		     Change the default domain name to name1 and the domain search list to name1,
		     name2,  etc. A maximum of 6 names separated by slashes (/) can be specified.
		     For example,
			 set srchlist=lcs.MIT.EDU/ai.MIT.EDU/MIT.EDU
		     sets the domain to lcs.MIT.EDU and the search list to the three names.  This
		     command  overrides the default domain name and search list of the set domain
		     command.  Use the set all command to display the list.
		     (Default = value based on hostname, /etc/resolv.conf or LOCALDOMAIN,  abbre-
		     viation = srchl)

	      [no]defname
		     If  set, append the default domain name to a single-component lookup request
		     (i.e., one that does not contain a period).
		     (Default = defname, abbreviation = [no]def)

	      [no]search
		     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, abbreviation = [no]sea)

	      port=value
		     Change the default TCP/UDP name server port to value.
		     (Default = 53, abbreviation = po)

	      querytype=value
	      type=value
		     Change the type of information query to one of:

		     A	       the host's Internet address.

		     CNAME     the canonical name for an alias.

		     HINFO     the host CPU and operating system type.

		     MINFO     the mailbox or mail list information.

		     MX        the mail exchanger.

		     NS        the name server for the named zone.

		     PTR       the host name if the query is an Internet address,  otherwise  the
			       pointer to other information.

		     SOA       the domain's ``start-of-authority'' information.

		     TXT       the text information.

		     UINFO     the user information.

		     WKS       the supported well-known services.

		     Other types (ANY, AXFR, MB, MD, MF, NULL) are described in the RFC-1035 doc-
		     ument.
		     (Default = A, abbreviations = q, ty)

	      [no]recurse
		     Tell the name server to query other servers if it does not have the informa-
		     tion.
		     (Default = recurse, abbreviation = [no]rec)

	      retry=number
		     Set  the  number  of  retries  to	number.  When a reply to a request is not
		     received within a certain amount of time (changed	with  set  timeout),  the
		     timeout  period  is doubled and the request is resent.  The retry value con-
		     trols how many times a request is resent before giving up.
		     (Default = 4, abbreviation = ret)

	      root=host
		     Change the name of the root server to host. This affects the root command.
		     (Default = ns.internic.net., abbreviation = ro)

	      timeout=number
		     Change the initial timeout interval for waiting for a reply to  number  sec-
		     onds.  Each retry doubles the timeout period.
		     (Default = 5 seconds, abbreviation = ti)

	      [no]vc Always use a virtual circuit when sending requests to the server.
		     (Default = novc, abbreviation = [no]v)

	      [no]ignoretc
		     Ignore packet truncation errors.
		     (Default = noignoretc, abbreviation = [no]ig)

DIAGNOSTICS
       If  the	lookup	request was not successful, an error message is printed.  Possible errors
       are:

       Timed out
	    The server did not respond to a request after a certain amount of time (changed  with
	    set timeout=value) and a certain number of retries (changed with set retry=value).

       No response from server
	    No name server is running on the server machine.

       No records
	    The  server  does  not  have resource records of the current query type for the host,
	    although the host name is valid.  The query type is specified with the set	querytype
	    command.

       Non-existent domain
	    The host or domain name does not exist.

       Connection refused
       Network is unreachable
	    The  connection  to  the name or finger server could not be made at the current time.
	    This error commonly occurs with ls and finger requests.

       Server failure
	    The name server found an internal inconsistency in its database and could not  return
	    a valid answer.

       Refused
	    The name server refused to service the request.

       Format error
	    The  name  server found that the request packet was not in the proper format.  It may
	    indicate an error in nslookup.

FILES
       /etc/resolv.conf 	       initial		  domain	     name	      and
				       name server addresses.
       $HOME/.nslookuprc	       user's initial options.
       /usr/share/misc/nslookup.help   summary of commands.

ENVIRONMENT
       HOSTALIASES    file containing host aliases.
       LOCALDOMAIN    overrides default domain.

SEE ALSO
       resolver(3), resolver(5), named(8),
       RFC-1034  ``Domain Names - Concepts and Facilities''
       RFC-1035  ``Domain Names - Implementation and Specification''

AUTHOR
       Andrew Cherenson

4.3 Berkeley Distribution		  June 24, 1990 			      NSLOOKUP(8)
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