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RedHat 9 (Linux i386) - man page for dig (redhat section 1)

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 administrators use dig to troubleshoot DNS problems because of
       its flexibility, 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 implementation of dig allows multiple lookups to  be  issued  from  the  command

       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

       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 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 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  sup-
       ported  in BIND9. The default query type "A", unless the -x option is supplied to indicate
       a reverse lookup.  A zone transfer can be requested by specifying a type of AXFR. When  an
       incremental zone transfer (IXFR) is required, type is set to ixfr=N.  The incremental 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 auto-
       matically 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 transaction 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 algo-
       rithm 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 strategies.

       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 +keyword=value.  The query options are:

	      Use  [do	not  use] TCP when querying name servers. The default behaviour is to use
	      UDP unless an AXFR or IXFR query is requested, in which case a  TCP  connection  is

	      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 provided for completeness.

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

	      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 automat-
	      ically 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 zone.

	      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 iter-
	      ative 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

	      toggles the printing of the initial comment in the output identifying  the  version
	      of  dig  and  the  query options that have been applied. This comment is printed by

	      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 supplied 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 com-

	      This query option toggles the printing of statistics: when the query was made,  the
	      size  of	the  reply and so on. The default behaviour is to print the query statis-

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

	      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

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

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

	      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 format with human-read-
	      able 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 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 sup-
       plied 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 standard 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 sup-
       plied. 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 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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