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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).

       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.

       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/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 sup‐
	      plied, 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
       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  -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
       being 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
       answer 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 compatibility  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

	      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
	      answer is returned. The default is to print the question section
	      as a comment.

	      Display [do not display] the answer  section  of	a  reply.  The
	      default 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
	      instead 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
	      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.

	      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
	      default  is  to  not try the next server which is the reverse of
	      normal 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 OPT record in the additional section of the query.

       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

       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

       dig +qr www.isc.org any -x 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
       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.



       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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