dig.docbook

非常好的dns解析软件

    </para>

  </refsect1>

  <refsect1>
    <title>QUERY OPTIONS</title>

    <para><command>dig</command>
      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.
    </para>

    <para>
      Each query option is identified by a keyword preceded by a plus sign
      (<literal>+</literal>).  Some keywords set or reset an
      option.  These may be preceded
      by the string <literal>no</literal> to negate the meaning of
      that keyword.  Other
      keywords assign values to options like the timeout interval.  They
      have the form <option>+keyword=value</option>.
      The query options are:

      <variablelist>

        <varlistentry>
          <term><option>+[no]tcp</option></term>
          <listitem>
            <para>
              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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]vc</option></term>
          <listitem>
            <para>
              Use [do not use] TCP when querying name servers.  This alternate
              syntax to <parameter>+[no]tcp</parameter> is
              provided for backwards
              compatibility.  The "vc" stands for "virtual circuit".
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]ignore</option></term>
          <listitem>
            <para>
              Ignore truncation in UDP responses instead of retrying with TCP.
               By
              default, TCP retries are performed.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+domain=somename</option></term>
          <listitem>
            <para>
              Set the search list to contain the single domain
              <parameter>somename</parameter>, as if specified in
              a
              <command>domain</command> directive in
              <filename>/etc/resolv.conf</filename>, and enable
              search list
              processing as if the <parameter>+search</parameter>
              option were given.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]search</option></term>
          <listitem>
            <para>
              Use [do not use] the search list defined by the searchlist or
              domain
              directive in <filename>resolv.conf</filename> (if
              any).
              The search list is not used by default.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]showsearch</option></term>
          <listitem>
            <para>
              Perform [do not perform] a search showing intermediate
	      results.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]defname</option></term>
          <listitem>
            <para>
              Deprecated, treated as a synonym for <parameter>+[no]search</parameter>
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]aaonly</option></term>
          <listitem>
            <para>
              Sets the "aa" flag in the query.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]aaflag</option></term>
          <listitem>
            <para>
              A synonym for <parameter>+[no]aaonly</parameter>.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]adflag</option></term>
          <listitem>
            <para>
              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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]cdflag</option></term>
          <listitem>
            <para>
              Set [do not set] the CD (checking disabled) bit in the query.
              This
              requests the server to not perform DNSSEC validation of
              responses.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]cl</option></term>
          <listitem>
            <para>
              Display [do not display] the CLASS when printing the record.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]ttlid</option></term>
          <listitem>
            <para>
              Display [do not display] the TTL when printing the record.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]recurse</option></term>
          <listitem>
            <para>
              Toggle the setting of the RD (recursion desired) bit in the
              query.
              This bit is set by default, which means <command>dig</command>
              normally sends recursive queries.  Recursion is automatically
              disabled
              when the <parameter>+nssearch</parameter> or
              <parameter>+trace</parameter> query options are
              used.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]nssearch</option></term>
          <listitem>
            <para>
              When this option is set, <command>dig</command>
              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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]trace</option></term>
          <listitem>
            <para>
              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, <command>dig</command> 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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]cmd</option></term>
          <listitem>
            <para>
              toggles the printing of the initial comment in the output
              identifying
              the version of <command>dig</command> and the query
              options that have
              been applied.  This comment is printed by default.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]short</option></term>
          <listitem>
            <para>
              Provide a terse answer.  The default is to print the answer in a
              verbose form.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]identify</option></term>
          <listitem>
            <para>
              Show [or do not show] the IP address and port number that
              supplied the
              answer when the <parameter>+short</parameter> 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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]comments</option></term>
          <listitem>
            <para>
              Toggle the display of comment lines in the output.  The default
              is to
              print comments.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]stats</option></term>
          <listitem>
            <para>
              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 statistics.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]qr</option></term>
          <listitem>
            <para>
              Print [do not print] the query as it is sent.
              By default, the query is not printed.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]question</option></term>
          <listitem>
            <para>
              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.
            </para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>+[no]answer</option></term>
          <listitem>
            <para>
              Display [do not display] the answer section of a reply.  The
              default
              is to display it.
            </para>