49dbdb0186eb23d87d685b96eaefa9ec3c71d9b8David Lawrence<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">

40f53fa8d9c6a4fc38c0014495e7a42b08f52481David Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refentry>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refentryinfo>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<date>Jun 30, 2000</date>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</refentryinfo>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refmeta>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refentrytitle>dig</refentrytitle>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<manvolnum>1</manvolnum>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refmiscinfo>BIND9</refmiscinfo>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</refmeta>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refnamediv>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refname>dig</refname>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refpurpose>DNS lookup utility</refpurpose>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</refnamediv>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refsynopsisdiv>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt>@server</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-b <replaceable class="parameter">address</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-c <replaceable class="parameter">class</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-f <replaceable class="parameter">filename</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-k <replaceable class="parameter">filename</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-p <replaceable class="parameter">port#</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-t <replaceable class="parameter">type</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-x <replaceable class="parameter">addr</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-y <replaceable class="parameter">name:key</replaceable></option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt>name</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt>type</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt>class</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt rep=repeat>queryopt</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg><option>-h</option></arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt rep=repeat>global-queryopt</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<arg choice=opt rep=repeat>query</arg>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</cmdsynopsis>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</refsynopsisdiv>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<refsect1>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<title>DESCRIPTION</title>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command> (domain information groper) is a flexible tool

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencefor interrogating DNS name servers. It performs DNS lookups and

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencedisplays the answers that are returned from the name server(s) that

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencewere queried. Most DNS administrators use <command>dig</command> to

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencetroubleshoot DNS problems because of its flexibility, ease of use and

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrenceclarity of output. Other lookup tools tend to have less functionality

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencethan <command>dig</command>.

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid LawrenceAlthough <command>dig</command> is normally used with command-line

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencearguments, it also has a batch mode of operation for reading lookup

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencerequests from a file. A brief summary of its command-line arguments

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrenceand options is printed when the <option>-h</option> option is given.

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid LawrenceUnlike earlier versions, the BIND9 implementation of

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command> allows multiple lookups to be issued from the

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrencecommand line.

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid LawrenceUnless it is told to query a specific name server,

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<command>dig</command> will try each of the servers listed in

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<filename>/etc/resolv.conf</filename>.

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence<para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid LawrenceWhen no command line arguments or options are given, will perform an

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid LawrenceNS query for "." (the root).

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</para>

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence

a904de0bc85cc3974a87a32deedb69d6a68ec36cDavid Lawrence</refsect1>

<refsect1>

<title>SIMPLE USAGE</title>

<para>

A typical invocation of <command>dig</command> looks like:

<programlisting> dig @server name type </programlisting> where:

<variablelist>

<varlistentry><term><constant>server</constant></term>

<listitem><para>

is the name or IP address of the name server to query. An IPv4

address can be provided in dotted-decimal notation. When the supplied

<parameter>server</parameter> argument is a hostname,

<command>dig</command> resolves that name before querying that name

server. If no <parameter>server</parameter> argument is provided,

<command>dig</command> consults <filename>/etc/resolv.conf</filename>

and queries the name servers listed there. The reply from the name

server that responds is displayed.

</para></listitem></varlistentry>

<varlistentry><term><constant>name</constant></term>

<listitem><para>

is the name of the resource record that is to be looked up.

</para></listitem></varlistentry>

<varlistentry><term><constant>type</constant></term>

<listitem><para>

indicates what type of query is required &mdash;

ANY, A, MX, SIG, etc.

<parameter>type</parameter> can be any valid query type. If no

<parameter>type</parameter> argument is supplied,

<command>dig</command> will perform a lookup for an A record.

</para></listitem></varlistentry>

</variablelist>

</para>

</refsect1>

<refsect1>

<title>OPTIONS</title>

<para>

The <option>-b</option> option sets the source IP address of the query

to <parameter>address</parameter>. This must be a valid address on

one of the host's network interfaces.

</para>

<para>

The default query class (IN for internet) is overridden by the

<option>-c</option> option. <parameter>class</parameter> is any valid

class, such as HS for Hesiod records or CH for CHAOSNET records.

</para>

<para>

The <option>-f</option> option makes <command>dig </command> operate

in batch mode by reading a list of lookup requests to process from the

file <parameter>filename</parameter>. 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

<command>dig</command> using the command-line interface.

</para>

<para>

If a non-standard port number is to be queried, the

<option>-p</option> option is used. <parameter>port#</parameter> is

the port number that <command>dig</command> 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.

</para>

<para>

The <option>-t</option> option sets the query type to

<parameter>type</parameter>. It can be any valid query type which is

supported in BIND9. The default query type "A", unless the

<option>-x</option> 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,

<parameter>type</parameter> is set to <literal>ixfr=N</literal>.

The incremental zone transfer will contain the changes made to the zone

since the serial number in the zone's SOA record was

<parameter>N</parameter>.

</para>

<para>

Reverse lookups - mapping addresses to names - are simplified by the

<option>-x</option> option. <parameter>addr</parameter> 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

<parameter>name</parameter>, <parameter>class</parameter> and

<parameter>type</parameter> arguments. <command>dig</command>

automatically performs a lookup for a name like

<literal>11.12.13.10.in-addr.arpa</literal> 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 <option>-n</option> (nibble) option.

</para>

<para>

To sign the DNS queries sent by <command>dig</command> and their

responses using transaction signatures (TSIG), specify a TSIG key file

using the <option>-k</option> option. You can also specify the TSIG

key itself on the command line using the <option>-y</option> option;

<parameter>name</parameter> is the name of the TSIG key and

<parameter>key</parameter> is the actual key. The key is a base-64

encoded string, typically generated by <citerefentry>

<refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>.

Caution should be taken when using the <option>-y</option> option on

multi-user systems as the key can be visible in the output from

<citerefentry> <refentrytitle>ps</refentrytitle><manvolnum>1

</manvolnum> </citerefentry> or in the shell's history file. When

using TSIG authentication with <command>dig</command>, 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

<command>key</command> and <command>server</command> statements in

<filename>named.conf</filename>.

</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]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>

This option does nothing. It is provided for compatibilty with old

versions of <command>dig</command> where it set an unimplemented

resolver flag.

</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]recursive</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></listitem></varlistentry>

<varlistentry><term><option>+[no]authority</option></term>

<listitem><para>

Display [do not display] the authority section of a reply. The

default is to display it.

</para></listitem></varlistentry>

<varlistentry><term><option>+[no]additional</option></term>

<listitem><para>

Display [do not display] the additional section of a reply.

The default is to display it.

</para></listitem></varlistentry>

<varlistentry><term><option>+[no]all</option></term>

<listitem><para>

Set or clear all display flags.

</para></listitem></varlistentry>

<varlistentry><term><option>+time=T</option></term>

<listitem><para>

Sets the timeout for a query to

<parameter>T</parameter> seconds. The default time out is 5 seconds.

An attempt to set <parameter>T</parameter> to less than 1 will result

in a query timeout of 1 second being applied.

</para></listitem></varlistentry>

<varlistentry><term><option>+tries=A</option></term>

<listitem><para>

Sets the number of times to retry UDP queries to server to

<parameter>T</parameter> instead of the default, 3. If

<parameter>T</parameter> is less than or equal to zero, the number of

retries is silently rounded up to 1.

</para></listitem></varlistentry>

<varlistentry><term><option>+ndots=D</option></term>

<listitem><para>

Set the number of dots that have to appear in

<parameter>name</parameter> to <parameter>D</parameter> for it to be

considered absolute. The default value is that defined using the

ndots statement in <filename>/etc/resolv.conf</filename>, 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

<option>search</option> or <option>domain</option> directive in

<filename>/etc/resolv.conf</filename>.

</para></listitem></varlistentry>

<varlistentry><term><option>+bufsize=B</option></term>

<listitem><para>

Set the UDP message buffer size advertised using EDNS0 to

<parameter>B</parameter> bytes. The maximum and minimum sizes of this

buffer are 65535 and 0 respectively. Values outside this range are

rounded up or down appropriately.

</para>

</listitem></varlistentry>

</variablelist>

</para>

</refsect1>

<refsect1>

<title>MULTIPLE QUERIES</title>

<para>

The BIND 9 implementation of <command>dig </command> supports

specifying multiple queries on the command line (in addition to

supporting the <option>-f</option> batch file option). Each of those

queries can be supplied with its own set of flags, options and query

options.

</para>

<para>

In this case, each <parameter>query</parameter> 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.

</para>

<para>

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 can be

overridden by a query-specific set of query options. For example:

<programlisting>

dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr

</programlisting>

shows how <command>dig</command> could be used from the command line

to make three lookups: an ANY query for <literal>www.isc.org</literal>, a

reverse lookup of 127.0.0.1 and a query for the NS records of

<literal>isc.org</literal>.

A global query option of <parameter>+qr</parameter> is applied, so

that <command>dig</command> shows the initial query it made for each

lookup. The final query has a local query option of

<parameter>+noqr</parameter> which means that <command>dig</command>

will not print the initial query when it looks up the NS records for

<literal>isc.org</literal>.

</para>

</refsect1>

<refsect1>

<title>FILES</title>

<para>

<filename>/etc/resolv.conf</filename>

</para>

</refsect1>

<refsect1>

<title>SEE ALSO</title>

<para>

<citerefentry>

<refentrytitle>host</refentrytitle><manvolnum>1</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>,

<citetitle>RFC1035</citetitle>.

</para>

</refsect1>

<refsect1>

<title>BUGS </title>

<para>

There are probably too many query options.

</para>

</refsect1>

</refentry>