Charles Steinkuehler's LEAF/LRP Website




     dig [@server] domain [<query-type>] [<query-class>] [+<query-option>]
         [-<dig-option>] [%comment]


     Dig (domain information groper) is a flexible command line tool which can
     be used to gather information from the Domain Name System servers.  Dig
     has two modes: simple interactive mode for a single query, and batch mode
     which executes a query for each in a list of several query lines. All
     query options are accessible from the command line.

     The usual simple use of dig will take the form:

                 dig @server domain query-type query-class


     server      may be either a domain name or a dot-notation Internet ad­
                 dress. If this optional field is omitted, dig will attempt to
                 use the default name server for your machine.

                 Note: If a domain name is specified, this will be resolved
                 using the domain name system resolver (i.e., BIND). If your
                 system does not support DNS, you may have to specify a dot-
                 notation address.  Alternatively, if there is a server at
                 your disposal somewhere,  all that is required is that
                 /etc/resolv.conf be present and indicate where the default
                 name servers reside,  so that server itself can be resolved.
                 See resolver(5) for information on /etc/resolv.conf. WARNING:
                 Changing /etc/resolv.conf will affect both the standard re­
                 solver library and (potentially) several programs which use
                 it.  As an option, the user may set the environment variable
                 LOCALRES to name a file which is to be used instead of
                 /etc/resolv.conf standard resolver (LOCALRESis specific to
                 the dig resolver and  is  not  referenced  by  the). If the
                 LOCALRES variable is not set or the specified file is not
                 readable, then /etc/resolv.conf will be used.

     domain      is the domain name for which you are requesting information.
                 See the -x option (documented in the OTHER OPTIONS subsection
                 of this section) for convenient way to specify inverse ad­
                 dress query.

     query-type  is the type of information (DNS query type) that you are re­
                 questing. If omitted, the default is ``a'' (T_A = address).
                 The following types are recognized:

                 a       T_A        network address
                 any     T_ANY      all/any information about specified domain
                 mx      T_MX       mail exchanger for the domain
                 ns      T_NS       name servers
                 soa     T_SOA      zone of authority record
                 hinfo   T_HINFO    host information
                 axfr    T_AXFR     zone transfer (must ask an authoritative
                 in      C_IN       Internet class domain
                 any     C_ANY      all/any class information

                 (See RFC 1035 for the complete list.)

                 Note: ``Any'' can be used to specify a class and/or a type of
                 query.  Dig will parse the first occurrence of ``any'' to
                 mean query-type = T_ANY. To specify query-class = C_ANY, you
                 must either specify ``any'' twice, or set query-class using
                 the -c option (see below).


                 ``%'' is used to included an argument that is simply not
                 parsed.  This may be useful  if running dig in batch mode.
                 Instead of resolving every @server-domain-name in a list of
                 queries, you can avoid the overhead of doing so, and still
                 have the domain name on the command line as a reference. Ex­

                             dig @ %venera.isi.edu mx isi.edu

     -<dig option>
                 ``-'' is used to specify an option which affects the opera­
                 tion of dig. The following options are currently available
                 (although not guaranteed to be useful):

                 -x dot-notation-address
                             Convenient form to specify inverse address map­
                             ping.  Instead of ``dig
                             addr.arpa'', one can simply ``dig -x

                 -f file     File for dig batch mode. The file contains a list
                             of query specifications ( dig command lines)
                             which are to be executed successively.  Lines be­
                             ginning with `;', `#', or `\n' are ignored.  Oth­
                             er options may still appear on command line, and
                             will be in effect for each batch query.

                 -T time     Time in seconds between start of successive
                             queries when running in batch mode. Can be used
                             to keep two or more batch dig commands running
                             roughly in sync.  Default is zero.

                 -p port     Port number. Query a name server listening to a
                             non-standard port number.  Default is 53.

                             After query returns, execute a ping(8) command
                             for response time comparison.  This rather unele­
                             gantly makes a call to the shell.  The last three
                             lines of statistics is printed for the command:

                 -c query-class
                             Specify class of query. May specify either an in­
                             teger value to be included in the class field or
                             use the abbreviated mnemonic as discussed above
                             (i.e., in = C_IN).

                 -k keydir:keyname
                             Sign the query with the TSIG key named keyname
                             that is in the directory keydir.

                 -envsav     This flag specifies that the dig environment (de­
                             faults, print options, etc.), after all of the
                             arguments are parsed, should be saved to a file
                             to become the default environment.  This is use­
                             ful if you do not like the standard set of de­
                             faults and do not desire to include a large num­
                             ber of options each time dig is used.  The envi­
                             ronment consists of resolver state variable
                             flags, timeout, and retries as well as the flags
                             detailing dig output (see below).  If the shell
                             environment variable LOCALDEF is set to the name
                             of a file, this is where the default dig environ­
                             ment is saved.  If not, the file ``DiG.env'' is
                             created in the current working directory.

                             Note: LOCALDEF is specific to the dig resolver,
                             and will not affect operation of the standard re­
                             solver library.

                             Each time dig is executed, it looks for
                             ``./DiG.env'' or the file specified by the shell
                             environment variable LOCALDEF. If such file ex­
                             ists and is readable, then the environment is re­
                             stored from this file before any arguments are

                 -envset     This flag only affects batch query runs. When
                             ``-envset'' is specified on a line in a dig batch
                             file, the dig environment after the arguments are
                             parsed becomes the default environment for the
                             duration of the batch file, or until the next
                             line which specifies ``-envset''.

                 -[no] stick
                             This flag only affects batch query runs.  It
                             specifies that the dig environment (as read ini­
                             tially or set by ``-envset'' switch) is to be re­
                             stored before each query (line) in a dig batch
                             file.  The default ``-nostick'' means that the
                             dig environment does not stick, hence options
                             specified on a single line in a dig batch file
                             will remain in effect for subsequent lines (i.e.
                             they are not restored to the ``sticky'' default).

                 currently available:

                 Keyword      Abbrev.  Meaning [default]

                 [no] debug     (deb)    turn on/off debugging mode [deb]
                 [no] d2                 turn on/off extra debugging mode
                 [no] recurse   (rec)    use/don't use recursive lookup [rec]
                 retry=#       (ret)     set number of retries to # [4]
                 time=#        (ti)      set timeout length to # seconds [4]
                 [no] ko                 keep open option (implies vc) [noko]
                 [no] vc                 use/don't use virtual circuit [novc]
                 [no] defname   (def)    use/don't use default domain name
                 [no] search    (sea)    use/don't use domain search list
                 domain=NAME   (do)      set default domain name to NAME
                 [no] ignore    (i)      ignore/don't ignore trunc. errors
                 [no] primary   (pr)     use/don't use primary server [nopr]
                 [no] aaonly    (aa)     authoritative query only flag [noaa]
                 [no] cmd                echo parsed arguments [cmd]
                 [no] stats     (st)     print query statistics [st]
                 [no] Header    (H)      print basic header [H]
                 [no] header    (he)     print header flags [he]
                 [no] ttlid     (tt)     print TTLs [tt]
                 [no] cl                 print class info [nocl]
                 [no] qr                 print outgoing query [noqr]
                 [no] reply     (rep)    print reply [rep]
                 [no] ques      (qu)     print question section [qu]
                 [no] answer    (an)     print answer section [an]
                 [no] author    (au)     print authoritative section [au]
                 [no] addit     (ad)     print additional section [ad]
                 pfdef                   set to default print flags
                 pfmin                   set to minimal default print flags
                 pfset=#                 set print flags to # (# can be
                 pfand=#                 bitwise and print flags with #
                 pfor=#                  bitwise or print flags with #

                 The retry and time options affect the retransmission strategy
                 used by the resolver library when sending datagram queries.
                 The algorithm is as follows:

                       for i = 0 to retry - 1
                           for j = 1 to num_servers
                               wait((time * (2**i)) / num_servers)

                 (Note: dig always uses a value of 1 for ``num_servers''.)

     tions, above.


                         initial domain name and name server addresses
     ./DiG.env           default save file for default options


     named(8),  resolver(3),  resolver(5),  nslookup(8).


     RFC 1035.


     Steve Hotz hotz@isi.edu


     Dig uses functions from nslookup(8) authored by Andrew Cherenson.


     Dig has a serious case of "creeping featurism" -- the result of consider­
     ing several potential uses during it's development.  It would probably
     benefit from a rigorous diet.  Similarly, the print flags and granularity
     of the items they specify make evident their rather ad hoc genesis.

     Dig does not consistently exit nicely (with appropriate status) when a
     problem occurs somewhere in the resolver (NOTE:most of the common exit
     cases are handled). This is particularly annoying when running in batch
     mode.  If it exits abnormally (and is not caught), the entire batch
     aborts; when such an event is trapped, dig simply continues with the next

4th Berkeley Distribution       August 30, 1990                              5

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