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21<!-- $Id: dig.docbook,v 1.47 2010/03/04 23:50:34 tbox Exp $ -->
22<refentry id="man.dig">
23
24  <refentryinfo>
25    <date>Jun 30, 2000</date>
26  </refentryinfo>
27
28  <refmeta>
29    <refentrytitle>dig</refentrytitle>
30    <manvolnum>1</manvolnum>
31    <refmiscinfo>BIND9</refmiscinfo>
32  </refmeta>
33
34  <refnamediv>
35    <refname>dig</refname>
36    <refpurpose>DNS lookup utility</refpurpose>
37  </refnamediv>
38
39  <docinfo>
40    <copyright>
41      <year>2004</year>
42      <year>2005</year>
43      <year>2006</year>
44      <year>2007</year>
45      <year>2008</year>
46      <year>2009</year>
47      <year>2010</year>
48      <holder>Internet Systems Consortium, Inc. ("ISC")</holder>
49    </copyright>
50    <copyright>
51      <year>2000</year>
52      <year>2001</year>
53      <year>2002</year>
54      <year>2003</year>
55      <holder>Internet Software Consortium.</holder>
56    </copyright>
57  </docinfo>
58
59  <refsynopsisdiv>
60    <cmdsynopsis>
61      <command>dig</command>
62      <arg choice="opt">@server</arg>
63      <arg><option>-b <replaceable class="parameter">address</replaceable></option></arg>
64      <arg><option>-c <replaceable class="parameter">class</replaceable></option></arg>
65      <arg><option>-f <replaceable class="parameter">filename</replaceable></option></arg>
66      <arg><option>-k <replaceable class="parameter">filename</replaceable></option></arg>
67      <arg><option>-m</option></arg>
68      <arg><option>-p <replaceable class="parameter">port#</replaceable></option></arg>
69      <arg><option>-q <replaceable class="parameter">name</replaceable></option></arg>
70      <arg><option>-t <replaceable class="parameter">type</replaceable></option></arg>
71      <arg><option>-x <replaceable class="parameter">addr</replaceable></option></arg>
72      <arg><option>-y <replaceable class="parameter"><optional>hmac:</optional>name:key</replaceable></option></arg>
73      <arg><option>-4</option></arg>
74      <arg><option>-6</option></arg>
75      <arg choice="opt">name</arg>
76      <arg choice="opt">type</arg>
77      <arg choice="opt">class</arg>
78      <arg choice="opt" rep="repeat">queryopt</arg>
79    </cmdsynopsis>
80
81    <cmdsynopsis>
82      <command>dig</command>
83      <arg><option>-h</option></arg>
84    </cmdsynopsis>
85
86    <cmdsynopsis>
87      <command>dig</command>
88      <arg choice="opt" rep="repeat">global-queryopt</arg>
89      <arg choice="opt" rep="repeat">query</arg>
90    </cmdsynopsis>
91  </refsynopsisdiv>
92
93  <refsect1>
94    <title>DESCRIPTION</title>
95    <para><command>dig</command>
96      (domain information groper) is a flexible tool
97      for interrogating DNS name servers.  It performs DNS lookups and
98      displays the answers that are returned from the name server(s) that
99      were queried.  Most DNS administrators use <command>dig</command> to
100      troubleshoot DNS problems because of its flexibility, ease of use and
101      clarity of output.  Other lookup tools tend to have less functionality
102      than <command>dig</command>.
103    </para>
104
105    <para>
106      Although <command>dig</command> is normally used with
107      command-line
108      arguments, it also has a batch mode of operation for reading lookup
109      requests from a file.  A brief summary of its command-line arguments
110      and options is printed when the <option>-h</option> option is given.
111      Unlike earlier versions, the BIND 9 implementation of
112      <command>dig</command> allows multiple lookups to be issued
113      from the
114      command line.
115    </para>
116
117    <para>
118      Unless it is told to query a specific name server,
119      <command>dig</command> will try each of the servers listed
120      in
121      <filename>/etc/resolv.conf</filename>.
122    </para>
123
124    <para>
125      When no command line arguments or options are given,
126      <command>dig</command> will perform an NS query for "." (the root).
127    </para>
128
129    <para>
130      It is possible to set per-user defaults for <command>dig</command> via
131      <filename>${HOME}/.digrc</filename>.  This file is read and
132      any options in it
133      are applied before the command line arguments.
134    </para>
135
136    <para>
137      The IN and CH class names overlap with the IN and CH top level
138      domains names.  Either use the <option>-t</option> and
139      <option>-c</option> options to specify the type and class, 
140      use the <option>-q</option> the specify the domain name, or
141      use "IN." and "CH." when looking up these top level domains.
142    </para>
143
144  </refsect1>
145
146  <refsect1>
147    <title>SIMPLE USAGE</title>
148
149    <para>
150      A typical invocation of <command>dig</command> looks like:
151      <programlisting> dig @server name type </programlisting>
152      where:
153
154      <variablelist>
155
156        <varlistentry>
157          <term><constant>server</constant></term>
158          <listitem>
159            <para>
160              is the name or IP address of the name server to query.  This can
161              be an IPv4
162              address in dotted-decimal notation or an IPv6
163              address in colon-delimited notation.  When the supplied
164              <parameter>server</parameter> argument is a
165              hostname,
166              <command>dig</command> resolves that name before
167              querying that name
168              server.  If no <parameter>server</parameter>
169              argument is provided,
170              <command>dig</command> consults <filename>/etc/resolv.conf</filename>
171              and queries the name servers listed there.  The reply from the
172              name
173              server that responds is displayed.
174            </para>
175          </listitem>
176        </varlistentry>
177
178        <varlistentry>
179          <term><constant>name</constant></term>
180          <listitem>
181            <para>
182              is the name of the resource record that is to be looked up.
183            </para>
184          </listitem>
185        </varlistentry>
186
187        <varlistentry>
188          <term><constant>type</constant></term>
189          <listitem>
190            <para>
191              indicates what type of query is required &mdash;
192              ANY, A, MX, SIG, etc.
193              <parameter>type</parameter> can be any valid query
194              type.  If no
195              <parameter>type</parameter> argument is supplied,
196              <command>dig</command> will perform a lookup for an
197              A record.
198            </para>
199          </listitem>
200        </varlistentry>
201
202      </variablelist>
203    </para>
204
205  </refsect1>
206
207  <refsect1>
208    <title>OPTIONS</title>
209
210    <para>
211      The <option>-b</option> option sets the source IP address of the query
212      to <parameter>address</parameter>.  This must be a valid
213      address on
214      one of the host's network interfaces or "0.0.0.0" or "::".  An optional
215      port
216      may be specified by appending "#&lt;port&gt;"
217    </para>
218
219    <para>
220      The default query class (IN for internet) is overridden by the
221      <option>-c</option> option.  <parameter>class</parameter> is
222      any valid
223      class, such as HS for Hesiod records or CH for Chaosnet records.
224    </para>
225
226    <para>
227      The <option>-f</option> option makes <command>dig </command>
228      operate
229      in batch mode by reading a list of lookup requests to process from the
230      file <parameter>filename</parameter>.  The file contains a
231      number of
232      queries, one per line.  Each entry in the file should be organized in
233      the same way they would be presented as queries to
234      <command>dig</command> using the command-line interface.
235    </para>
236
237    <para>
238      The <option>-m</option> option enables memory usage debugging.
239      <!-- It enables ISC_MEM_DEBUGTRACE and ISC_MEM_DEBUGRECORD
240           documented in include/isc/mem.h -->
241    </para>
242
243    <para>
244      If a non-standard port number is to be queried, the
245      <option>-p</option> option is used.  <parameter>port#</parameter> is
246      the port number that <command>dig</command> will send its
247      queries
248      instead of the standard DNS port number 53.  This option would be used
249      to test a name server that has been configured to listen for queries
250      on a non-standard port number.
251    </para>
252
253    <para>
254      The <option>-4</option> option forces <command>dig</command>
255      to only
256      use IPv4 query transport.  The <option>-6</option> option forces
257      <command>dig</command> to only use IPv6 query transport.
258    </para>
259
260    <para>
261      The <option>-t</option> option sets the query type to
262      <parameter>type</parameter>.  It can be any valid query type
263      which is
264      supported in BIND 9.  The default query type is "A", unless the
265      <option>-x</option> option is supplied to indicate a reverse lookup.
266      A zone transfer can be requested by specifying a type of AXFR.  When
267      an incremental zone transfer (IXFR) is required,
268      <parameter>type</parameter> is set to <literal>ixfr=N</literal>.
269      The incremental zone transfer will contain the changes made to the zone
270      since the serial number in the zone's SOA record was
271      <parameter>N</parameter>.
272    </para>
273
274    <para>
275      The <option>-q</option> option sets the query name to 
276      <parameter>name</parameter>.  This useful do distinguish the
277      <parameter>name</parameter> from other arguments.
278    </para>
279
280    <para>
281      Reverse lookups &mdash; mapping addresses to names &mdash; are simplified by the
282      <option>-x</option> option.  <parameter>addr</parameter> is
283      an IPv4
284      address in dotted-decimal notation, or a colon-delimited IPv6 address.
285      When this option is used, there is no need to provide the
286      <parameter>name</parameter>, <parameter>class</parameter> and
287      <parameter>type</parameter> arguments.  <command>dig</command>
288      automatically performs a lookup for a name like
289      <literal>11.12.13.10.in-addr.arpa</literal> and sets the
290      query type and
291      class to PTR and IN respectively.  By default, IPv6 addresses are
292      looked up using nibble format under the IP6.ARPA domain.
293      To use the older RFC1886 method using the IP6.INT domain
294      specify the <option>-i</option> option.  Bit string labels (RFC2874)
295      are now experimental and are not attempted.
296    </para>
297
298    <para>
299      To sign the DNS queries sent by <command>dig</command> and
300      their
301      responses using transaction signatures (TSIG), specify a TSIG key file
302      using the <option>-k</option> option.  You can also specify the TSIG
303      key itself on the command line using the <option>-y</option> option;
304      <parameter>hmac</parameter> is the type of the TSIG, default HMAC-MD5,
305      <parameter>name</parameter> is the name of the TSIG key and
306      <parameter>key</parameter> is the actual key.  The key is a
307      base-64
308      encoded string, typically generated by
309      <citerefentry>
310        <refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>
311      </citerefentry>.
312
313      Caution should be taken when using the <option>-y</option> option on
314      multi-user systems as the key can be visible in the output from
315      <citerefentry>
316        <refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum>
317      </citerefentry>
318      or in the shell's history file.  When
319      using TSIG authentication with <command>dig</command>, the name
320      server that is queried needs to know the key and algorithm that is
321      being used.  In BIND, this is done by providing appropriate
322      <command>key</command> and <command>server</command> statements in
323      <filename>named.conf</filename>.
324    </para>
325
326  </refsect1>
327
328  <refsect1>
329    <title>QUERY OPTIONS</title>
330
331    <para><command>dig</command>
332      provides a number of query options which affect
333      the way in which lookups are made and the results displayed.  Some of
334      these set or reset flag bits in the query header, some determine which
335      sections of the answer get printed, and others determine the timeout
336      and retry strategies.
337    </para>
338
339    <para>
340      Each query option is identified by a keyword preceded by a plus sign
341      (<literal>+</literal>).  Some keywords set or reset an
342      option.  These may be preceded
343      by the string <literal>no</literal> to negate the meaning of
344      that keyword.  Other
345      keywords assign values to options like the timeout interval.  They
346      have the form <option>+keyword=value</option>.
347      The query options are:
348
349      <variablelist>
350
351        <varlistentry>
352          <term><option>+[no]tcp</option></term>
353          <listitem>
354            <para>
355              Use [do not use] TCP when querying name servers.  The default
356              behavior is to use UDP unless an AXFR or IXFR query is
357              requested, in
358              which case a TCP connection is used.
359            </para>
360          </listitem>
361        </varlistentry>
362
363        <varlistentry>
364          <term><option>+[no]vc</option></term>
365          <listitem>
366            <para>
367              Use [do not use] TCP when querying name servers.  This alternate
368              syntax to <parameter>+[no]tcp</parameter> is
369              provided for backwards
370              compatibility.  The "vc" stands for "virtual circuit".
371            </para>
372          </listitem>
373        </varlistentry>
374
375        <varlistentry>
376          <term><option>+[no]ignore</option></term>
377          <listitem>
378            <para>
379              Ignore truncation in UDP responses instead of retrying with TCP.
380               By
381              default, TCP retries are performed.
382            </para>
383          </listitem>
384        </varlistentry>
385
386        <varlistentry>
387          <term><option>+domain=somename</option></term>
388          <listitem>
389            <para>
390              Set the search list to contain the single domain
391              <parameter>somename</parameter>, as if specified in
392              a
393              <command>domain</command> directive in
394              <filename>/etc/resolv.conf</filename>, and enable
395              search list
396              processing as if the <parameter>+search</parameter>
397              option were given.
398            </para>
399          </listitem>
400        </varlistentry>
401
402        <varlistentry>
403          <term><option>+[no]search</option></term>
404          <listitem>
405            <para>
406              Use [do not use] the search list defined by the searchlist or
407              domain
408              directive in <filename>resolv.conf</filename> (if
409              any).
410              The search list is not used by default.
411            </para>
412          </listitem>
413        </varlistentry>
414
415        <varlistentry>
416          <term><option>+[no]showsearch</option></term>
417          <listitem>
418            <para>
419              Perform [do not perform] a search showing intermediate
420	      results.
421            </para>
422          </listitem>
423        </varlistentry>
424
425        <varlistentry>
426          <term><option>+[no]defname</option></term>
427          <listitem>
428            <para>
429              Deprecated, treated as a synonym for <parameter>+[no]search</parameter>
430            </para>
431          </listitem>
432        </varlistentry>
433
434        <varlistentry>
435          <term><option>+[no]aaonly</option></term>
436          <listitem>
437            <para>
438              Sets the "aa" flag in the query.
439            </para>
440          </listitem>
441        </varlistentry>
442
443        <varlistentry>
444          <term><option>+[no]aaflag</option></term>
445          <listitem>
446            <para>
447              A synonym for <parameter>+[no]aaonly</parameter>.
448            </para>
449          </listitem>
450        </varlistentry>
451
452        <varlistentry>
453          <term><option>+[no]adflag</option></term>
454	  <listitem>
455	    <para>
456	      Set [do not set] the AD (authentic data) bit in the
457	      query.  This requests the server to return whether
458	      all of the answer and authority sections have all
459	      been validated as secure according to the security
460	      policy of the server.  AD=1 indicates that all records
461	      have been validated as secure and the answer is not
462	      from a OPT-OUT range.  AD=0 indicate that some part
463	      of the answer was insecure or not validated.
464	    </para>
465	  </listitem>
466	</varlistentry>
467
468        <varlistentry>
469          <term><option>+[no]cdflag</option></term>
470          <listitem>
471            <para>
472              Set [do not set] the CD (checking disabled) bit in the query.
473              This
474              requests the server to not perform DNSSEC validation of
475              responses.
476            </para>
477          </listitem>
478        </varlistentry>
479
480        <varlistentry>
481          <term><option>+[no]cl</option></term>
482          <listitem>
483            <para>
484              Display [do not display] the CLASS when printing the record.
485            </para>
486          </listitem>
487        </varlistentry>
488
489        <varlistentry>
490          <term><option>+[no]ttlid</option></term>
491          <listitem>
492            <para>
493              Display [do not display] the TTL when printing the record.
494            </para>
495          </listitem>
496        </varlistentry>
497
498        <varlistentry>
499          <term><option>+[no]recurse</option></term>
500          <listitem>
501            <para>
502              Toggle the setting of the RD (recursion desired) bit in the
503              query.
504              This bit is set by default, which means <command>dig</command>
505              normally sends recursive queries.  Recursion is automatically
506              disabled
507              when the <parameter>+nssearch</parameter> or
508              <parameter>+trace</parameter> query options are
509              used.
510            </para>
511          </listitem>
512        </varlistentry>
513
514        <varlistentry>
515          <term><option>+[no]nssearch</option></term>
516          <listitem>
517            <para>
518              When this option is set, <command>dig</command>
519              attempts to find the
520              authoritative name servers for the zone containing the name
521              being
522              looked up and display the SOA record that each name server has
523              for the
524              zone.
525            </para>
526          </listitem>
527        </varlistentry>
528
529        <varlistentry>
530          <term><option>+[no]trace</option></term>
531          <listitem>
532            <para>
533              Toggle tracing of the delegation path from the root name servers
534              for
535              the name being looked up.  Tracing is disabled by default.  When
536              tracing is enabled, <command>dig</command> makes
537              iterative queries to
538              resolve the name being looked up.  It will follow referrals from
539              the
540              root servers, showing the answer from each server that was used
541              to
542              resolve the lookup.
543            </para>
544          </listitem>
545        </varlistentry>
546
547        <varlistentry>
548          <term><option>+[no]cmd</option></term>
549          <listitem>
550            <para>
551              Toggles the printing of the initial comment in the output
552              identifying
553              the version of <command>dig</command> and the query
554              options that have
555              been applied.  This comment is printed by default.
556            </para>
557          </listitem>
558        </varlistentry>
559
560        <varlistentry>
561          <term><option>+[no]short</option></term>
562          <listitem>
563            <para>
564              Provide a terse answer.  The default is to print the answer in a
565              verbose form.
566            </para>
567          </listitem>
568        </varlistentry>
569
570        <varlistentry>
571          <term><option>+[no]identify</option></term>
572          <listitem>
573            <para>
574              Show [or do not show] the IP address and port number that
575              supplied the
576              answer when the <parameter>+short</parameter> option
577              is enabled.  If
578              short form answers are requested, the default is not to show the
579              source address and port number of the server that provided the
580              answer.
581            </para>
582          </listitem>
583        </varlistentry>
584
585        <varlistentry>
586          <term><option>+[no]comments</option></term>
587          <listitem>
588            <para>
589              Toggle the display of comment lines in the output.  The default
590              is to
591              print comments.
592            </para>
593          </listitem>
594        </varlistentry>
595
596        <varlistentry>
597          <term><option>+[no]stats</option></term>
598          <listitem>
599            <para>
600              This query option toggles the printing of statistics: when the
601              query
602              was made, the size of the reply and so on.  The default
603              behavior is
604              to print the query statistics.
605            </para>
606          </listitem>
607        </varlistentry>
608
609        <varlistentry>
610          <term><option>+[no]qr</option></term>
611          <listitem>
612            <para>
613              Print [do not print] the query as it is sent.
614              By default, the query is not printed.
615            </para>
616          </listitem>
617        </varlistentry>
618
619        <varlistentry>
620          <term><option>+[no]question</option></term>
621          <listitem>
622            <para>
623              Print [do not print] the question section of a query when an
624              answer is
625              returned.  The default is to print the question section as a
626              comment.
627            </para>
628          </listitem>
629        </varlistentry>
630
631        <varlistentry>
632          <term><option>+[no]answer</option></term>
633          <listitem>
634            <para>
635              Display [do not display] the answer section of a reply.  The
636              default
637              is to display it.
638            </para>
639          </listitem>
640        </varlistentry>
641
642        <varlistentry>
643          <term><option>+[no]authority</option></term>
644          <listitem>
645            <para>
646              Display [do not display] the authority section of a reply.  The
647              default is to display it.
648            </para>
649          </listitem>
650        </varlistentry>
651
652        <varlistentry>
653          <term><option>+[no]additional</option></term>
654          <listitem>
655            <para>
656              Display [do not display] the additional section of a reply.
657              The default is to display it.
658            </para>
659          </listitem>
660        </varlistentry>
661
662        <varlistentry>
663          <term><option>+[no]all</option></term>
664          <listitem>
665            <para>
666              Set or clear all display flags.
667            </para>
668          </listitem>
669        </varlistentry>
670
671        <varlistentry>
672          <term><option>+time=T</option></term>
673          <listitem>
674            <para>
675
676              Sets the timeout for a query to
677              <parameter>T</parameter> seconds.  The default
678	      timeout is 5 seconds.
679              An attempt to set <parameter>T</parameter> to less
680              than 1 will result
681              in a query timeout of 1 second being applied.
682            </para>
683          </listitem>
684        </varlistentry>
685
686        <varlistentry>
687          <term><option>+tries=T</option></term>
688          <listitem>
689            <para>
690              Sets the number of times to try UDP queries to server to
691              <parameter>T</parameter> instead of the default, 3.
692              If
693              <parameter>T</parameter> is less than or equal to
694              zero, the number of
695              tries is silently rounded up to 1.
696            </para>
697          </listitem>
698        </varlistentry>
699
700        <varlistentry>
701          <term><option>+retry=T</option></term>
702          <listitem>
703            <para>
704              Sets the number of times to retry UDP queries to server to
705              <parameter>T</parameter> instead of the default, 2.
706              Unlike
707              <parameter>+tries</parameter>, this does not include
708              the initial
709              query.
710            </para>
711          </listitem>
712        </varlistentry>
713
714        <varlistentry>
715          <term><option>+ndots=D</option></term>
716          <listitem>
717            <para>
718              Set the number of dots that have to appear in
719              <parameter>name</parameter> to <parameter>D</parameter> for it to be
720              considered absolute.  The default value is that defined using
721              the
722              ndots statement in <filename>/etc/resolv.conf</filename>, or 1 if no
723              ndots statement is present.  Names with fewer dots are
724              interpreted as
725              relative names and will be searched for in the domains listed in
726              the
727              <option>search</option> or <option>domain</option> directive in
728              <filename>/etc/resolv.conf</filename>.
729            </para>
730          </listitem>
731        </varlistentry>
732
733        <varlistentry>
734          <term><option>+bufsize=B</option></term>
735          <listitem>
736            <para>
737              Set the UDP message buffer size advertised using EDNS0 to
738              <parameter>B</parameter> bytes.  The maximum and minimum sizes
739	      of this buffer are 65535 and 0 respectively.  Values outside
740	      this range are rounded up or down appropriately.  
741	      Values other than zero will cause a EDNS query to be sent.
742            </para>
743          </listitem>
744        </varlistentry>
745
746	<varlistentry>
747	  <term><option>+edns=#</option></term>
748	  <listitem>
749	    <para>
750	       Specify the EDNS version to query with.  Valid values
751	       are 0 to 255.  Setting the EDNS version will cause a
752	       EDNS query to be sent.  <option>+noedns</option> clears the
753	       remembered EDNS version.
754	    </para>
755	  </listitem>
756	</varlistentry>
757
758        <varlistentry>
759          <term><option>+[no]multiline</option></term>
760          <listitem>
761            <para>
762              Print records like the SOA records in a verbose multi-line
763              format with human-readable comments.  The default is to print
764              each record on a single line, to facilitate machine parsing
765              of the <command>dig</command> output.
766            </para>
767          </listitem>
768        </varlistentry>
769
770	<varlistentry>
771	  <term><option>+[no]onesoa</option></term>
772	  <listitem>
773	    <para>
774	      Print only one (starting) SOA record when performing
775	      an AXFR. The default is to print both the starting and
776	      ending SOA records.
777	    </para>
778	  </listitem>
779	</varlistentry>
780
781        <varlistentry>
782          <term><option>+[no]fail</option></term>
783          <listitem>
784            <para>
785              Do not try the next server if you receive a SERVFAIL.  The
786              default is
787              to not try the next server which is the reverse of normal stub
788              resolver
789              behavior.
790            </para>
791          </listitem>
792        </varlistentry>
793
794        <varlistentry>
795          <term><option>+[no]besteffort</option></term>
796          <listitem>
797            <para>
798              Attempt to display the contents of messages which are malformed.
799              The default is to not display malformed answers.
800            </para>
801          </listitem>
802        </varlistentry>
803
804        <varlistentry>
805          <term><option>+[no]dnssec</option></term>
806          <listitem>
807            <para>
808              Requests DNSSEC records be sent by setting the DNSSEC OK bit
809              (DO)
810              in the OPT record in the additional section of the query.
811            </para>
812          </listitem>
813        </varlistentry>
814
815        <varlistentry>
816          <term><option>+[no]sigchase</option></term>
817          <listitem>
818            <para>
819              Chase DNSSEC signature chains.  Requires dig be compiled with
820              -DDIG_SIGCHASE.
821            </para>
822          </listitem>
823        </varlistentry>
824
825        <varlistentry>
826          <term><option>+trusted-key=####</option></term>
827          <listitem>
828            <para>
829              Specifies a file containing trusted keys to be used with
830	      <option>+sigchase</option>.  Each DNSKEY record must be
831	      on its own line.
832            </para>
833	    <para>
834	      If not specified, <command>dig</command> will look for
835	      <filename>/etc/trusted-key.key</filename> then
836	      <filename>trusted-key.key</filename> in the current directory.
837	    </para>
838	    <para>
839              Requires dig be compiled with -DDIG_SIGCHASE.
840	    </para>
841          </listitem>
842        </varlistentry>
843
844        <varlistentry>
845          <term><option>+[no]topdown</option></term>
846          <listitem>
847            <para>
848              When chasing DNSSEC signature chains perform a top-down
849              validation.
850              Requires dig be compiled with -DDIG_SIGCHASE.
851            </para>
852          </listitem>
853        </varlistentry>
854
855        <varlistentry>
856          <term><option>+[no]nsid</option></term>
857          <listitem>
858            <para>
859              Include an EDNS name server ID request when sending a query.
860            </para>
861          </listitem>
862        </varlistentry>
863
864
865      </variablelist>
866
867    </para>
868  </refsect1>
869
870  <refsect1>
871    <title>MULTIPLE QUERIES</title>
872
873    <para>
874      The BIND 9 implementation of <command>dig </command>
875      supports
876      specifying multiple queries on the command line (in addition to
877      supporting the <option>-f</option> batch file option).  Each of those
878      queries can be supplied with its own set of flags, options and query
879      options.
880    </para>
881
882    <para>
883      In this case, each <parameter>query</parameter> argument
884      represent an
885      individual query in the command-line syntax described above.  Each
886      consists of any of the standard options and flags, the name to be
887      looked up, an optional query type and class and any query options that
888      should be applied to that query.
889    </para>
890
891    <para>
892      A global set of query options, which should be applied to all queries,
893      can also be supplied.  These global query options must precede the
894      first tuple of name, class, type, options, flags, and query options
895      supplied on the command line.  Any global query options (except
896      the <option>+[no]cmd</option> option) can be
897      overridden by a query-specific set of query options.  For example:
898      <programlisting>
899dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr
900</programlisting>
901      shows how <command>dig</command> could be used from the
902      command line
903      to make three lookups: an ANY query for <literal>www.isc.org</literal>, a
904      reverse lookup of 127.0.0.1 and a query for the NS records of
905      <literal>isc.org</literal>.
906
907      A global query option of <parameter>+qr</parameter> is
908      applied, so
909      that <command>dig</command> shows the initial query it made
910      for each
911      lookup.  The final query has a local query option of
912      <parameter>+noqr</parameter> which means that <command>dig</command>
913      will not print the initial query when it looks up the NS records for
914      <literal>isc.org</literal>.
915    </para>
916
917  </refsect1>
918
919  <refsect1>
920    <title>IDN SUPPORT</title>
921    <para>
922      If <command>dig</command> has been built with IDN (internationalized
923      domain name) support, it can accept and display non-ASCII domain names.
924      <command>dig</command> appropriately converts character encoding of
925      domain name before sending a request to DNS server or displaying a
926      reply from the server.
927      If you'd like to turn off the IDN support for some reason, defines
928      the <envar>IDN_DISABLE</envar> environment variable.
929      The IDN support is disabled if the variable is set when 
930      <command>dig</command> runs.
931    </para>
932  </refsect1>
933
934  <refsect1>
935    <title>FILES</title>
936    <para><filename>/etc/resolv.conf</filename>
937    </para>
938    <para><filename>${HOME}/.digrc</filename>
939    </para>
940  </refsect1>
941
942  <refsect1>
943    <title>SEE ALSO</title>
944    <para><citerefentry>
945        <refentrytitle>host</refentrytitle><manvolnum>1</manvolnum>
946      </citerefentry>,
947      <citerefentry>
948        <refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>
949      </citerefentry>,
950      <citerefentry>
951        <refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>
952      </citerefentry>,
953      <citetitle>RFC1035</citetitle>.
954    </para>
955  </refsect1>
956
957  <refsect1>
958    <title>BUGS</title>
959    <para>
960      There are probably too many query options.
961    </para>
962  </refsect1>
963</refentry><!--
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