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DIG(1)									DIG(1)

       dig - DNS lookup	utility

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

       dig [ -h	]

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

       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).

       A typical invocation of dig looks like:

	dig @server name type


       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/re-
	      solv.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.

       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.

       The  default  query class (IN for internet) is overridden by the	-c op-
       tion. 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 or-
       ganised 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  -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 and	sets the query
       type and	class to PTR and IN respectively. By default,  IPv6  addresses
       are looked up using the IP6.ARPA	domain and binary labels as defined in
       RFC2874.	To use the older RFC1886 method	using the IP6.INT  domain  and
       "nibble"	labels,	specify	the -n (nibble)	option.

       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 be-
       ing used. In BIND, this is done by providing appropriate	key and	server
       statements in named.conf.

       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 an-
       swer get	printed, and others determine the timeout  and	retry  strate-

       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:

	      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.

	      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".

	      Ignore truncation	in UDP responses instead of retrying with TCP.
	      By default, TCP retries are performed.

	      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.

	      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.

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

	      This option does nothing.	It is provided for  compatibilty  with
	      old versions of dig where	it set an unimplemented	resolver flag.

	      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.

	      Set [do not set] the CD (checking	disabled) bit  in  the	query.
	      This requests the	server to not perform DNSSEC validation	of re-

	      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.

	      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

	      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.

	      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.

	      Provide  a terse answer. The default is to print the answer in a
	      verbose form.

	      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

	      Toggle the display of comment lines in the output.  The  default
	      is to print comments.

	      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.

	      Print  [do  not print] the query as it is	sent.  By default, the
	      query is not printed.

	      Print [do	not print] the question	section	of a query when	an an-
	      swer  is	returned. The default is to print the question section
	      as a comment.

	      Display [do not display] the answer section of a reply. The  de-
	      fault is to display it.

	      Display  [do  not	display] the authority section of a reply. The
	      default is to display it.

	      Display [do not display] the additional section of a reply.  The
	      default is to display it.

	      Set or clear all display flags.

	      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.

	      Sets the number of times to retry	UDP queries to server to T in-
	      stead of the default, 3. If T is less than or equal to zero, the
	      number of	retries	is silently rounded up to 1.

	      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 us-
	      ing  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.

	      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.

	      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.

	      Do not try the next server if you	receive	a  SERVFAIL.  The  de-
	      fault is to not try the next server which	is the reverse of nor-
	      mal stub resolver	behaviour.

	      Attempt to display the contents of messages which	are malformed.
	      The default is to	not display malformed answers.

	      Requests	DNSSEC	records	 be  sent by setting the DNSSEC	OK bit
	      (DO) in the the OPT record in  the  additional  section  of  the

       The  BIND 9 implementation of dig  supports specifying multiple queries
       on the command line (in addition	to supporting the -f  batch  file  op-
       tion). 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

       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 op-
       tion) can be overridden by a query-specific set of query	 options.  For

       dig +qr any -x ns +noqr

       shows  how  dig	could  be  used	 from  the  command line to make three
       lookups:	an ANY query for, a	reverse	 lookup	 of
       and  a  query  for the NS records of  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


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

       There are probably too many query options.

BIND9				 Jun 30, 2000				DIG(1)


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