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DIG(1)									DIG(1)

NAME
       dig - DNS lookup	utility

SYNOPSIS
       dig  [  @server	]  [ -b	address	]  [ -c	class ]	 [ -f filename ]  [ -k
       filename	]  [ -p	port# ]	 [ -t type ]  [	-x addr	]  [ -y	name:key ]   [
       -4 ]  [ -6 ]  [ name ]  [ type ]	 [ class ]  [ queryopt... ]

       dig [ -h	]

       dig [ global-queryopt...	]  [ query... ]

DESCRIPTION
       dig  (domain  information  groper) is a flexible	tool for interrogating
       DNS name	servers. It performs DNS lookups and displays the answers that
       are returned from the name server(s) that were queried. Most DNS	admin-
       istrators use dig to troubleshoot DNS problems because of its flexibil-
       ity, ease of use	and clarity of output. Other lookup tools tend to have
       less functionality than dig.

       Although	dig is normally	used with command-line arguments, it also  has
       a  batch	 mode  of operation for	reading	lookup requests	from a file. A
       brief summary of	its command-line arguments and options is printed when
       the -h option is	given.	Unlike earlier versions, the BIND9 implementa-
       tion of dig allows multiple lookups to be issued	from the command line.

       Unless it is told to query a specific name server, dig will try each of
       the servers listed in /etc/resolv.conf.

       When no command line arguments or options are given, will perform an NS
       query for "." (the root).

       It  is  possible	 to  set per-user defaults for dig via ${HOME}/.digrc.
       This file is read and any options in it are applied before the  command
       line arguments.

SIMPLE USAGE
       A typical invocation of dig looks like:

	dig @server name type

       where:

       server is  the name or IP address of the	name server to query. This can
	      be an IPv4 address in dotted-decimal notation or an IPv6 address
	      in  colon-delimited  notation. When the supplied server argument
	      is a hostname, dig resolves that name before querying that  name
	      server.	If  no	server	argument  is  provided,	 dig  consults
	      /etc/resolv.conf and queries the name servers listed there.  The
	      reply from the name server that responds is displayed.

       name   is the name of the resource record that is to be looked up.

       type   indicates	 what  type  of	 query is required -- ANY, A, MX, SIG,
	      etc.  type can be	any valid query	type. If no type  argument  is
	      supplied,	dig will perform a lookup for an A record.

OPTIONS
       The  -b option sets the source IP address of the	query to address. This
       must be a valid address on one of  the  host's  network	interfaces  or
       "0.0.0.0"  or  "::".  An	 optional  port	 may be	specified by appending
       "#<port>"

       The default query class (IN for	internet)  is  overridden  by  the  -c
       option.	class  is any valid class, such	as HS for Hesiod records or CH
       for CHAOSNET records.

       The -f option makes dig	operate	in batch mode by  reading  a  list  of
       lookup  requests	to process from	the file filename. The file contains a
       number of queries, one per line.	Each  entry  in	 the  file  should  be
       organised  in  the  same	 way they would	be presented as	queries	to dig
       using the command-line interface.

       If a non-standard port number is	to be queried, the -p option is	 used.
       port#  is the port number that dig will send its	queries	instead	of the
       standard	DNS port number	53. This option	would be used to test  a  name
       server that has been configured to listen for queries on	a non-standard
       port number.

       The -4 option forces dig	to only	 use  IPv4  query  transport.  The  -6
       option forces dig to only use IPv6 query	transport.

       The  -t	option	sets the query type to type. It	can be any valid query
       type which is supported in BIND9. The default query  type  "A",	unless
       the  -x option is supplied to indicate a	reverse	lookup.	 A zone	trans-
       fer can be requested by specifying a type of AXFR. When an  incremental
       zone transfer (IXFR) is required, type is set to	ixfr=N.	 The incremen-
       tal zone	transfer will contain the changes made to the zone  since  the
       serial number in	the zone's SOA record was N.

       Reverse lookups - mapping addresses to names - are simplified by	the -x
       option. addr is an IPv4 address in dotted-decimal notation, or a	colon-
       delimited  IPv6 address.	 When this option is used, there is no need to
       provide the name, class and type	arguments. dig automatically  performs
       a  lookup  for  a name like 11.12.13.10.in-addr.arpa and	sets the query
       type and	class to PTR and IN respectively. By default,  IPv6  addresses
       are  looked  up	using nibble format under the IP6.ARPA domain.	To use
       the older RFC1886 method	 using	the  IP6.INT  domain  specify  the  -i
       option.	Bit  string  labels (RFC2874) are now experimental and are not
       attempted.

       To sign the DNS queries sent by dig and their responses using  transac-
       tion  signatures	 (TSIG),  specify a TSIG key file using	the -k option.
       You can also specify the	TSIG key itself	on the command line using  the
       -y  option; name	is the name of the TSIG	key and	key is the actual key.
       The key is a base-64 encoded string, typically generated	by dnssec-key-
       gen(8).	Caution	should be taken	when using the -y option on multi-user
       systems as the key can be visible in the	output from ps(1)  or  in  the
       shell's history file. When using	TSIG authentication with dig, the name
       server that is queried needs to know the	 key  and  algorithm  that  is
       being  used.  In	 BIND,	this  is done by providing appropriate key and
       server statements in named.conf.

QUERY OPTIONS
       dig provides a number of	query options which affect the	way  in	 which
       lookups	are made and the results displayed. Some of these set or reset
       flag bits in the	query header, some determine  which  sections  of  the
       answer  get printed, and	others determine the timeout and retry strate-
       gies.

       Each query option is identified by a keyword preceded by	 a  plus  sign
       (+). Some keywords set or reset an option. These	may be preceded	by the
       string no to negate the meaning of that keyword.	Other keywords	assign
       values  to  options like	the timeout interval. They have	the form +key-
       word=value.  The	query options are:

       +[no]tcp
	      Use [do not use] TCP when	querying name servers. The default be-
	      haviour is to use	UDP unless an AXFR or IXFR query is requested,
	      in which case a TCP connection is	used.

       +[no]vc
	      Use [do not use] TCP when	querying name servers. This  alternate
	      syntax  to +[no]tcp is provided for backwards compatibility. The
	      "vc" stands for "virtual circuit".

       +[no]ignore
	      Ignore truncation	in UDP responses instead of retrying with TCP.
	      By default, TCP retries are performed.

       +domain=somename
	      Set the search list to contain the single	domain somename, as if
	      specified	in a domain directive in /etc/resolv.conf, and	enable
	      search list processing as	if the +search option were given.

       +[no]search
	      Use  [do	not  use] the search list defined by the searchlist or
	      domain directive in resolv.conf (if any).	 The  search  list  is
	      not used by default.

       +[no]defname
	      Deprecated, treated as a synonym for +[no]search

       +[no]aaonly
	      Sets the "aa" flag in the	query.

       +[no]aaflag
	      A	synonym	for +[no]aaonly.

       +[no]adflag
	      Set  [do	not set] the AD	(authentic data) bit in	the query. The
	      AD bit currently has a standard meaning only in  responses,  not
	      in  queries, but the ability to set the bit in the query is pro-
	      vided for	completeness.

       +[no]cdflag
	      Set [do not set] the CD (checking	disabled) bit  in  the	query.
	      This  requests  the  server  to not perform DNSSEC validation of
	      responses.

       +[no]cl
	      Display [do not display] the CLASS when printing the record.

       +[no]ttlid
	      Display [do not display] the TTL when printing the record.

       +[no]recurse
	      Toggle the setting of the	RD  (recursion	desired)  bit  in  the
	      query.   This  bit  is  set by default, which means dig normally
	      sends recursive queries.	Recursion  is  automatically  disabled
	      when the +nssearch or +trace query options are used.

       +[no]nssearch
	      When  this option	is set,	dig attempts to	find the authoritative
	      name servers for the zone	containing the name  being  looked  up
	      and  display  the	 SOA  record that each name server has for the
	      zone.

       +[no]trace
	      Toggle tracing of	the delegation path from the root name servers
	      for  the	name  being looked up. Tracing is disabled by default.
	      When tracing is enabled, dig makes iterative queries to  resolve
	      the name being looked up.	It will	follow referrals from the root
	      servers, showing the answer from each server that	 was  used  to
	      resolve the lookup.

       +[no]cmd
	      toggles  the printing of the initial comment in the output iden-
	      tifying the version of dig and the query options that have  been
	      applied. This comment is printed by default.

       +[no]short
	      Provide  a terse answer. The default is to print the answer in a
	      verbose form.

       +[no]identify
	      Show [or do not show] the	IP address and port number  that  sup-
	      plied  the  answer  when	the +short option is enabled. If short
	      form answers are requested, the  default	is  not	 to  show  the
	      source  address  and port	number of the server that provided the
	      answer.

       +[no]comments
	      Toggle the display of comment lines in the output.  The  default
	      is to print comments.

       +[no]stats
	      This  query  option toggles the printing of statistics: when the
	      query was	made, the size of the reply and	so on. The default be-
	      haviour is to print the query statistics.

       +[no]qr
	      Print  [do  not print] the query as it is	sent.  By default, the
	      query is not printed.

       +[no]question
	      Print [do	not print] the question	section	of  a  query  when  an
	      answer is	returned. The default is to print the question section
	      as a comment.

       +[no]answer
	      Display [do not display] the answer  section  of	a  reply.  The
	      default is to display it.

       +[no]authority
	      Display  [do  not	display] the authority section of a reply. The
	      default is to display it.

       +[no]additional
	      Display [do not display] the additional section of a reply.  The
	      default is to display it.

       +[no]all
	      Set or clear all display flags.

       +time=T
	      Sets  the	timeout	for a query to T seconds. The default time out
	      is 5 seconds.  An	attempt	to set T to less than 1	will result in
	      a	query timeout of 1 second being	applied.

       +tries=T
	      Sets  the	 number	 of  times  to	try UDP	queries	to server to T
	      instead of the default, 3. If T is less than or equal  to	 zero,
	      the number of tries is silently rounded up to 1.

       +retry=T
	      Sets  the	 number	 of  times to retry UDP	queries	to server to T
	      instead of the default, 2. Unlike	+tries,	this does not  include
	      the initial query.

       +ndots=D
	      Set  the	number of dots that have to appear in name to D	for it
	      to be considered absolute. The default  value  is	 that  defined
	      using  the ndots statement in /etc/resolv.conf, or 1 if no ndots
	      statement	is present. Names with fewer dots are  interpreted  as
	      relative names and will be searched for in the domains listed in
	      the search or domain directive in	/etc/resolv.conf.

       +bufsize=B
	      Set the UDP message buffer size  advertised  using  EDNS0	 to  B
	      bytes.  The  maximum  and	minimum	sizes of this buffer are 65535
	      and 0 respectively. Values outside this range are	rounded	up  or
	      down appropriately.

       +[no]multiline
	      Print  records like the SOA records in a verbose multi-line for-
	      mat with human-readable comments.	The default is to  print  each
	      record  on  a  single line, to facilitate	machine	parsing	of the
	      dig output.

       +[no]fail
	      Do not try the next  server  if  you  receive  a	SERVFAIL.  The
	      default  is  to  not try the next	server which is	the reverse of
	      normal stub resolver behaviour.

       +[no]besteffort
	      Attempt to display the contents of messages which	are malformed.
	      The default is to	not display malformed answers.

       +[no]dnssec
	      Requests	DNSSEC	records	 be  sent by setting the DNSSEC	OK bit
	      (DO) in the OPT record in	the additional section of the query.

       +[no]sigchase
	      Chase DNSSEC signature chains. Requires  dig  be	compiled  with
	      -DDIG_SIGCHASE.

       +trusted-key=####
	      Specify  a  trusted key to be used with +sigchase.  Requires dig
	      be compiled with -DDIG_SIGCHASE.

       +[no]topdown
	      When chasing DNSSEC signature chains perform a top down  valida-
	      tion.  Requires dig be compiled with -DDIG_SIGCHASE.

MULTIPLE QUERIES
       The  BIND 9 implementation of dig  supports specifying multiple queries
       on the command line (in	addition  to  supporting  the  -f  batch  file
       option).	 Each  of  those  queries  can be supplied with	its own	set of
       flags, options and query	options.

       In this case, each query	argument represent an individual query in  the
       command-line  syntax described above. Each consists of any of the stan-
       dard options and	flags, the name	to be looked  up,  an  optional	 query
       type  and  class	 and  any query	options	that should be applied to that
       query.

       A global	set of query options, which should be applied to all  queries,
       can also	be supplied. These global query	options	must precede the first
       tuple of	name, class, type, options, flags, and query options  supplied
       on  the	command	 line.	Any  global query options (except the +[no]cmd
       option) can be overridden by a query-specific set of query options. For
       example:

       dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr

       shows  how  dig	could  be  used	 from  the  command line to make three
       lookups:	an ANY query for www.isc.org, a	reverse	 lookup	 of  127.0.0.1
       and  a  query  for the NS records of isc.org.  A	global query option of
       +qr is applied, so that dig shows the initial query it  made  for  each
       lookup.	The  final query has a local query option of +noqr which means
       that dig	will not print the initial query  when	it  looks  up  the  NS
       records for isc.org.

FILES
       /etc/resolv.conf

       ${HOME}/.digrc

SEE ALSO
       host(1),	named(8), dnssec-keygen(8), RFC1035.

BUGS
       There are probably too many query options.

BIND9				 Jun 30, 2000				DIG(1)

NAME | SYNOPSIS | DESCRIPTION | SIMPLE USAGE | OPTIONS | QUERY OPTIONS | MULTIPLE QUERIES | FILES | SEE ALSO | BUGS

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