9e77d51069a97a21c68184134a0c9847e95490ffMark Andrews<
div class="cmdsynopsis"><
p><
code class="command">dig</
code> [@server] [<
code class="option">-b <
em class="replaceable"><
code>address</
code></
em></
code>] [<
code class="option">-c <
em class="replaceable"><
code>class</
code></
em></
code>] [<
code class="option">-f <
em class="replaceable"><
code>filename</
code></
em></
code>] [<
code class="option">-k <
em class="replaceable"><
code>filename</
code></
em></
code>] [<
code class="option">-p <
em class="replaceable"><
code>port#</
code></
em></
code>] [<
code class="option">-q <
em class="replaceable"><
code>name</
code></
em></
code>] [<
code class="option">-t <
em class="replaceable"><
code>type</
code></
em></
code>] [<
code class="option">-x <
em class="replaceable"><
code>addr</
code></
em></
code>] [<
code class="option">-y <
em class="replaceable"><
code>[<
span class="optional">hmac:</
span>]name:key</
code></
em></
code>] [<
code class="option">-4</
code>] [<
code class="option">-6</
code>] [name] [type] [class] [queryopt...]</
p></
div>
<
div class="variablelist"><
dl>
<
dt><
span class="term"><
code class="constant">server</
code></
span></
dt>
is the name or IP address of the name server to query. This can
address in dotted-decimal notation or an IPv6
address in colon-delimited notation. When the supplied
<
em class="parameter"><
code>server</
code></
em> argument is a
<
span><
strong class="command">dig</
strong></
span> resolves that name before
server. If no <
em class="parameter"><
code>server</
code></
em>
<
span><
strong class="command">dig</
strong></
span> consults <
code class="filename">/
etc/
resolv.conf</
code>
and queries the name servers listed there. The reply from the
server that responds is displayed.
<
dt><
span class="term"><
code class="constant">name</
code></
span></
dt>
is the name of the resource record that is to be looked up.
<
dt><
span class="term"><
code class="constant">type</
code></
span></
dt>
indicates what type of query is required —
<
em class="parameter"><
code>type</
code></
em> can be any valid query
<
em class="parameter"><
code>type</
code></
em> argument is supplied,
<
span><
strong class="command">dig</
strong></
span> will perform a lookup for an
<
div class="refsect1" lang="en">
<
a name="id2553097"></
a><
h2>OPTIONS</
h2>
The <
code class="option">-b</
code> option sets the source IP address of the query
to <
em class="parameter"><
code>address</
code></
em>. This must be a valid
one of the host's network interfaces or "0.0.0.0" or "::". An optional
may be specified by appending "#<port>"
The default query class (IN for internet) is overridden by the
<
code class="option">-c</
code> option. <
em class="parameter"><
code>class</
code></
em> is
class, such as HS for Hesiod records or CH for CHAOSNET records.
The <
code class="option">-f</
code> option makes <
span><
strong class="command">dig </
strong></
span>
in batch mode by reading a list of lookup requests to process from the
file <
em class="parameter"><
code>filename</
code></
em>. The file contains a
queries, one per line. Each entry in the file should be organised in
the same way they would be presented as queries to
<
span><
strong class="command">dig</
strong></
span> using the command-line interface.
If a non-standard port number is to be queried, the
<
code class="option">-p</
code> option is used. <
em class="parameter"><
code>port#</
code></
em> is
the port number that <
span><
strong class="command">dig</
strong></
span> will send its
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 <
code class="option">-4</
code> option forces <
span><
strong class="command">dig</
strong></
span>
use IPv4 query transport. The <
code class="option">-6</
code> option forces
<
span><
strong class="command">dig</
strong></
span> to only use IPv6 query transport.
The <
code class="option">-t</
code> option sets the query type to
<
em class="parameter"><
code>type</
code></
em>. It can be any valid query type
supported in BIND9. The default query type "A", unless the
<
code class="option">-x</
code> 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,
<
em class="parameter"><
code>type</
code></
em> is set to <
code class="literal">ixfr=N</
code>.
The incremental zone transfer will contain the changes made to the zone
since the serial number in the zone's SOA record was
<
em class="parameter"><
code>N</
code></
em>.
The <
code class="option">-q</
code> option sets the query name to
<
em class="parameter"><
code>name</
code></
em>. This useful do distingish the
<
em class="parameter"><
code>name</
code></
em> from other arguments.
Reverse lookups - mapping addresses to names - are simplified by the
<
code class="option">-x</
code> option. <
em class="parameter"><
code>addr</
code></
em> is
address in dotted-decimal notation, or a colon-delimited IPv6 address.
When this option is used, there is no need to provide the
<
em class="parameter"><
code>name</
code></
em>, <
em class="parameter"><
code>class</
code></
em> and
<
em class="parameter"><
code>type</
code></
em> arguments. <
span><
strong class="command">dig</
strong></
span>
automatically performs a lookup for a name like
class to PTR and IN respectively. By default, IPv6 addresses are
looked up using nibble format under the
IP6.ARPA domain.
To use the older RFC1886 method using the
IP6.INT domain
specify the <
code class="option">-i</
code> option. Bit string labels (RFC2874)
are now experimental and are not attempted.
To sign the DNS queries sent by <
span><
strong class="command">dig</
strong></
span> and
responses using transaction signatures (TSIG), specify a TSIG key file
using the <
code class="option">-k</
code> option. You can also specify the TSIG
key itself on the command line using the <
code class="option">-y</
code> option;
<
em class="parameter"><
code>hmac</
code></
em> is the type of the TSIG, default HMAC-MD5,
<
em class="parameter"><
code>name</
code></
em> is the name of the TSIG key and
<
em class="parameter"><
code>key</
code></
em> is the actual key. The key is a
encoded string, typically generated by
<
span class="citerefentry"><
span class="refentrytitle">dnssec-keygen</
span>(8)</
span>.
Caution should be taken when using the <
code class="option">-y</
code> option on
multi-user systems as the key can be visible in the output from
<
span class="citerefentry"><
span class="refentrytitle">ps</
span>(1)</
span>
or in the shell's history file. When
using TSIG authentication with <
span><
strong class="command">dig</
strong></
span>, 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
<
span><
strong class="command">key</
strong></
span> and <
span><
strong class="command">server</
strong></
span> statements in
<
div class="refsect1" lang="en">
<
a name="id2603128"></
a><
h2>QUERY OPTIONS</
h2>
<
p><
span><
strong class="command">dig</
strong></
span>
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
Each query option is identified by a keyword preceded by a plus sign
(<
code class="literal">+</
code>). Some keywords set or reset an
option. These may be preceded
by the string <
code class="literal">no</
code> to negate the meaning of
keywords assign values to options like the timeout interval. They
have the form <
code class="option">+keyword=value</
code>.
<
div class="variablelist"><
dl>
<
dt><
span class="term"><
code class="option">+[no]tcp</
code></
span></
dt>
Use [do not use] TCP when querying name servers. The default
behaviour is to use UDP unless an AXFR or IXFR query is
which case a TCP connection is used.
<
dt><
span class="term"><
code class="option">+[no]vc</
code></
span></
dt>
Use [do not use] TCP when querying name servers. This alternate
syntax to <
em class="parameter"><
code>+[no]tcp</
code></
em> is
compatibility. The "vc" stands for "virtual circuit".
<
dt><
span class="term"><
code class="option">+[no]ignore</
code></
span></
dt>
Ignore truncation in UDP responses instead of retrying with TCP.
default, TCP retries are performed.
<
dt><
span class="term"><
code class="option">+domain=somename</
code></
span></
dt>
Set the search list to contain the single domain
<
em class="parameter"><
code>somename</
code></
em>, as if specified in
<
span><
strong class="command">domain</
strong></
span> directive in
processing as if the <
em class="parameter"><
code>+search</
code></
em>
<
dt><
span class="term"><
code class="option">+[no]search</
code></
span></
dt>
Use [do not use] the search list defined by the searchlist or
directive in <
code class="filename">
resolv.conf</
code> (if
The search list is not used by default.
<
dt><
span class="term"><
code class="option">+[no]showsearch</
code></
span></
dt>
Perform [do not perform] a search showing intermediate
<
dt><
span class="term"><
code class="option">+[no]defname</
code></
span></
dt>
Deprecated, treated as a synonym for <
em class="parameter"><
code>+[no]search</
code></
em>
<
dt><
span class="term"><
code class="option">+[no]aaonly</
code></
span></
dt>
Sets the "aa" flag in the query.
<
dt><
span class="term"><
code class="option">+[no]aaflag</
code></
span></
dt>
A synonym for <
em class="parameter"><
code>+[no]aaonly</
code></
em>.
<
dt><
span class="term"><
code class="option">+[no]adflag</
code></
span></
dt>
Set [do not set] the AD (authentic data) bit in the query. The
currently has a standard meaning only in responses, not in
but the ability to set the bit in the query is provided for
<
dt><
span class="term"><
code class="option">+[no]cdflag</
code></
span></
dt>
Set [do not set] the CD (checking disabled) bit in the query.
requests the server to not perform DNSSEC validation of
<
dt><
span class="term"><
code class="option">+[no]cl</
code></
span></
dt>
Display [do not display] the CLASS when printing the record.
<
dt><
span class="term"><
code class="option">+[no]ttlid</
code></
span></
dt>
Display [do not display] the TTL when printing the record.
<
dt><
span class="term"><
code class="option">+[no]recurse</
code></
span></
dt>
Toggle the setting of the RD (recursion desired) bit in the
This bit is set by default, which means <
span><
strong class="command">dig</
strong></
span>
normally sends recursive queries. Recursion is automatically
when the <
em class="parameter"><
code>+nssearch</
code></
em> or
<
em class="parameter"><
code>+trace</
code></
em> query options are
<
dt><
span class="term"><
code class="option">+[no]nssearch</
code></
span></
dt>
When this option is set, <
span><
strong class="command">dig</
strong></
span>
authoritative name servers for the zone containing the name
looked up and display the SOA record that each name server has
<
dt><
span class="term"><
code class="option">+[no]trace</
code></
span></
dt>
Toggle tracing of the delegation path from the root name servers
the name being looked up. Tracing is disabled by default. When
tracing is enabled, <
span><
strong class="command">dig</
strong></
span> makes
resolve the name being looked up. It will follow referrals from
root servers, showing the answer from each server that was used
<
dt><
span class="term"><
code class="option">+[no]cmd</
code></
span></
dt>
toggles the printing of the initial comment in the output
the version of <
span><
strong class="command">dig</
strong></
span> and the query
been applied. This comment is printed by default.
<
dt><
span class="term"><
code class="option">+[no]short</
code></
span></
dt>
Provide a terse answer. The default is to print the answer in a
<
dt><
span class="term"><
code class="option">+[no]identify</
code></
span></
dt>
Show [or do not show] the IP address and port number that
answer when the <
em class="parameter"><
code>+short</
code></
em> option
short form answers are requested, the default is not to show the
source address and port number of the server that provided the
<
dt><
span class="term"><
code class="option">+[no]comments</
code></
span></
dt>
Toggle the display of comment lines in the output. The default
<
dt><
span class="term"><
code class="option">+[no]stats</
code></
span></
dt>
This query option toggles the printing of statistics: when the
was made, the size of the reply and so on. The default
to print the query statistics.
<
dt><
span class="term"><
code class="option">+[no]qr</
code></
span></
dt>
Print [do not print] the query as it is sent.
By default, the query is not printed.
<
dt><
span class="term"><
code class="option">+[no]question</
code></
span></
dt>
Print [do not print] the question section of a query when an
returned. The default is to print the question section as a
<
dt><
span class="term"><
code class="option">+[no]answer</
code></
span></
dt>
Display [do not display] the answer section of a reply. The
<
dt><
span class="term"><
code class="option">+[no]authority</
code></
span></
dt>
Display [do not display] the authority section of a reply. The
default is to display it.
<
dt><
span class="term"><
code class="option">+[no]additional</
code></
span></
dt>
Display [do not display] the additional section of a reply.
The default is to display it.
<
dt><
span class="term"><
code class="option">+[no]all</
code></
span></
dt>
Set or clear all display flags.
<
dt><
span class="term"><
code class="option">+time=T</
code></
span></
dt>
Sets the timeout for a query to
<
em class="parameter"><
code>T</
code></
em> seconds. The default time
An attempt to set <
em class="parameter"><
code>T</
code></
em> to less
in a query timeout of 1 second being applied.
<
dt><
span class="term"><
code class="option">+tries=T</
code></
span></
dt>
Sets the number of times to try UDP queries to server to
<
em class="parameter"><
code>T</
code></
em> instead of the default, 3.
<
em class="parameter"><
code>T</
code></
em> is less than or equal to
tries is silently rounded up to 1.
<
dt><
span class="term"><
code class="option">+retry=T</
code></
span></
dt>
Sets the number of times to retry UDP queries to server to
<
em class="parameter"><
code>T</
code></
em> instead of the default, 2.
<
em class="parameter"><
code>+tries</
code></
em>, this does not include
<
dt><
span class="term"><
code class="option">+ndots=D</
code></
span></
dt>
Set the number of dots that have to appear in
<
em class="parameter"><
code>name</
code></
em> to <
em class="parameter"><
code>D</
code></
em> for it to be
considered absolute. The default value is that defined using
ndots statement in <
code class="filename">/
etc/
resolv.conf</
code>, or 1 if no
ndots statement is present. Names with fewer dots are
relative names and will be searched for in the domains listed in
<
code class="option">search</
code> or <
code class="option">domain</
code> directive in
<
dt><
span class="term"><
code class="option">+bufsize=B</
code></
span></
dt>
Set the UDP message buffer size advertised using EDNS0 to
<
em class="parameter"><
code>B</
code></
em> bytes. The maximum and minimum sizes
of this buffer are 65535 and 0 respectively. Values outside
this range are rounded up or down appropriately.
Values other than zero will cause a EDNS query to be sent.
<
dt><
span class="term"><
code class="option">+edns=#</
code></
span></
dt>
Specify the EDNS version to query with. Valid values
are 0 to 255. Setting the EDNS version will cause a
EDNS query to be sent. <
code class="option">+noedns</
code> clears the
<
dt><
span class="term"><
code class="option">+[no]multiline</
code></
span></
dt>
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 <
span><
strong class="command">dig</
strong></
span> output.
<
dt><
span class="term"><
code class="option">+[no]fail</
code></
span></
dt>
Do not try the next server if you receive a SERVFAIL. The
to not try the next server which is the reverse of normal stub
<
dt><
span class="term"><
code class="option">+[no]besteffort</
code></
span></
dt>
Attempt to display the contents of messages which are malformed.
The default is to not display malformed answers.
<
dt><
span class="term"><
code class="option">+[no]dnssec</
code></
span></
dt>
Requests DNSSEC records be sent by setting the DNSSEC OK bit
in the OPT record in the additional section of the query.
<
dt><
span class="term"><
code class="option">+[no]sigchase</
code></
span></
dt>
Chase DNSSEC signature chains. Requires dig be compiled with
<
dt><
span class="term"><
code class="option">+trusted-key=####</
code></
span></
dt>
Specifies a file containing trusted keys to be used with
<
code class="option">+sigchase</
code>. Each DNSKEY record must be
If not specified <
span><
strong class="command">dig</
strong></
span> will look for
Requires dig be compiled with -DDIG_SIGCHASE.
<
dt><
span class="term"><
code class="option">+[no]topdown</
code></
span></
dt>
When chasing DNSSEC signature chains perform a top down
Requires dig be compiled with -DDIG_SIGCHASE.
<
div class="refsect1" lang="en">
<
a name="id2628349"></
a><
h2>MULTIPLE QUERIES</
h2>
The BIND 9 implementation of <
span><
strong class="command">dig </
strong></
span>
specifying multiple queries on the command line (in addition to
supporting the <
code class="option">-f</
code> batch file option). Each of those
queries can be supplied with its own set of flags, options and query
In this case, each <
em class="parameter"><
code>query</
code></
em> argument
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 <
code class="option">+[no]cmd</
code> option) can be
overridden by a query-specific set of query options. For example:
<
pre class="programlisting">
shows how <
span><
strong class="command">dig</
strong></
span> could be used from the
to make three lookups: an ANY query for <
code class="literal">
www.isc.org</
code>, a
reverse lookup of 127.0.0.1 and a query for the NS records of
<
code class="literal">
isc.org</
code>.
A global query option of <
em class="parameter"><
code>+qr</
code></
em> is
that <
span><
strong class="command">dig</
strong></
span> shows the initial query it made
lookup. The final query has a local query option of
<
em class="parameter"><
code>+noqr</
code></
em> which means that <
span><
strong class="command">dig</
strong></
span>
will not print the initial query when it looks up the NS records for
<
code class="literal">
isc.org</
code>.
<
div class="refsect1" lang="en">
<
a name="id2628435"></
a><
h2>IDN SUPPORT</
h2>
If <
span><
strong class="command">dig</
strong></
span> has been built with IDN (internationalized
domain name) support, it can accept and display non-ASCII domain names.
<
span><
strong class="command">dig</
strong></
span> appropriately converts character encoding of
domain name before sending a request to DNS server or displaying a
If you'd like to turn off the IDN support for some reason, defines
the <
code class="envar">IDN_DISABLE</
code> environment variable.
The IDN support is disabled if the variable is set when
<
span><
strong class="command">dig</
strong></
span> runs.
<
div class="refsect1" lang="en">
<
a name="id2628464"></
a><
h2>FILES</
h2>
<
p><
code class="filename">${HOME}/.digrc</
code>
<
div class="refsect1" lang="en">
<
a name="id2628485"></
a><
h2>SEE ALSO</
h2>
<
p><
span class="citerefentry"><
span class="refentrytitle">host</
span>(1)</
span>,
<
span class="citerefentry"><
span class="refentrytitle">named</
span>(8)</
span>,
<
span class="citerefentry"><
span class="refentrytitle">dnssec-keygen</
span>(8)</
span>,
<
em class="citetitle">RFC1035</
em>.
<
div class="refsect1" lang="en">
<
a name="id2628522"></
a><
h2>BUGS</
h2>
There are probably too many query options.
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