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 ]  [
       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 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 imple-
       mentation 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).

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 sup-
	      plied, 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.

       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 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 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  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-keygen(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
       +keyword=value.	The query options are:

       +[no]tcp
	      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 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
	      This option does nothing. It is provided for compatibilty with old versions of dig where it set an unimplemented resolver flag.

       +[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 provided 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]recursive
	      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 identifying 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 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 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 behav-
	      iour 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 retry UDP queries to server to T instead of the default, 3. If T is less than or equal to zero, the num-
	      ber of retries is silently rounded up to 1.

       +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 format 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 the OPT record in the additional section of the query.

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
       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 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

SEE ALSO

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

BUGS

       There are probably too many query options.

BIND9								   Jun 30, 2000 							    DIG(1)