>] [name] [type] [class] [queryopt...]</
P> [global-queryopt...] [query...]</
P> (domain information groper) is a flexible tool
for interrogating DNS name servers. It performs DNS lookups and
displays the answers that are returned from the name server(s) that
were queried. Most DNS administrators use <
Btroubleshoot DNS problems because of its flexibility, ease of use and
clarity of output. Other lookup tools tend to have less functionality
> is normally used with command-line
arguments, it also has a batch mode of operation for reading lookup
requests from a file. A brief summary of its command-line arguments
and options is printed when the <
TTUnlike earlier versions, the BIND9 implementation of
> allows multiple lookups to be issued from the
>Unless it is told to query a specific name server,
> will try each of the servers listed in
>When no command line arguments or options are given, will perform an
NS query for "." (the root).</
P>It is possible to set per-user defaults for <
B>. This file is read and any options in it
are applied before the command line arguments.</
P>A typical invocation of <
B> dig @server name type </
PRE>is the name or IP address of the name server to query. This can be an IPv4
address in dotted-decimal notation or an IPv6
address in colon-delimited notation. When the supplied
> argument is a hostname,
> resolves that name before querying that name
and queries the name servers listed there. The reply from the name
server that responds is displayed.</
P>is the name of the resource record that is to be looked up.</
P>indicates what type of query is required —
> can be any valid query type. If no
> will perform a lookup for an A record.</
P> option sets the source IP address of the query
>. This must be a valid address on
one of the host's network interfaces or "0.0.0.0" or "::". An optional port
may be specified by appending "#<port>"</
P>The default query class (IN for internet) is overridden by the
class, such as HS for Hesiod records or CH for CHAOSNET records.</
Pin batch mode by reading a list of lookup requests to process from the
>. 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
> using the command-line interface.</
P>If a non-standard port number is to be queried, the
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.</
P> option sets the query type to
>. It can be any valid query type which is
supported in BIND9. The default query type "A", unless the
> 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,
The incremental zone transfer will contain the changes made to the zone
since the serial number in the zone's SOA record was
>Reverse lookups - mapping addresses to names - are simplified by the
address in dotted-decimal notation, or a colon-delimited IPv6 address.
When this option is used, there is no need to provide the
automatically performs a lookup for a name like
> and sets the query type and
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
> option. Bit string labels (RFC2874)
are now experimental and are not attempted.</
P>To sign the DNS queries sent by <
Bresponses using transaction signatures (TSIG), specify a TSIG key file
> option. You can also specify the TSIG
key itself on the command line using the <
TT> is the name of the TSIG key and
> is the actual key. The key is a base-64
encoded string, typically generated by <
SPANCaution should be taken when using the <
TTmulti-user systems as the key can be visible in the output from
> or in the shell's history file. When
using TSIG authentication with <
Bserver that is queried needs to know the key and algorithm that is
being used. In BIND, this is done by providing appropriate
> 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
>). Some keywords set or reset an option. These may be preceded
> to negate the meaning of that keyword. Other
keywords assign values to options like the timeout interval. They
>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.</
P>Use [do not use] TCP when querying name servers. This alternate
> is provided for backwards
compatibility. The "vc" stands for "virtual circuit".</
P>Ignore truncation in UDP responses instead of retrying with TCP. By
default, TCP retries are performed.</
P>Set the search list to contain the single domain
>, and enable search list
>Use [do not use] the search list defined by the searchlist or domain
The search list is not used by default.</
P>Deprecated, treated as a synonym for <
TT>This option does nothing. It is provided for compatibility with old
> where it set an unimplemented
>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
>Set [do not set] the CD (checking disabled) bit in the query. This
requests the server to not perform DNSSEC validation of responses.</
P>Display [do not display] the CLASS when printing the record.</
P>Display [do not display] the TTL when printing the record.</
P>Toggle the setting of the RD (recursion desired) bit in the query.
This bit is set by default, which means <
Bnormally sends recursive queries. Recursion is automatically disabled
> query options are used.</
P>When this option is set, <
Bauthoritative name servers for the zone containing the name being
looked up and display the SOA record that each name server has for the
>Toggle tracing of the delegation path from the root name servers for
the name being looked up. Tracing is disabled by default. When
> 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
>toggles the printing of the initial comment in the output identifying
> and the query options that have
been applied. This comment is printed by default.</
P>Provide a terse answer. The default is to print the answer in a
>Show [or do not show] the IP address and port number that supplied the
short form answers are requested, the default is not to show the
source address and port number of the server that provided the answer.</
P>Toggle the display of comment lines in the output. The default is to
>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.</
P>Print [do not print] the query as it is sent.
By default, the query is not printed.</
P>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.</
P>Display [do not display] the answer section of a reply. The default
>Display [do not display] the authority section of a reply. The
default is to display it.</
P>Display [do not display] the additional section of a reply.
The default is to display it.</
P>Set or clear all display flags.</
P> Sets the timeout for a query to
> seconds. The default time out is 5 seconds.
> to less than 1 will result
in a query timeout of 1 second being applied.</
P>Sets the number of times to try UDP queries to server to
> instead of the default, 3. If
> is less than or equal to zero, the number of
tries is silently rounded up to 1.</
P>Sets the number of times to retry UDP queries to server to
> instead of the default, 2. Unlike
>, this does not include the initial
>Set the number of dots that have to appear in
considered absolute. The default value is that defined using the
ndots statement is present. Names with fewer dots are interpreted as
relative names and will be searched for in the domains listed in the
>Set the UDP message buffer size advertised using EDNS0 to
> bytes. The maximum and minimum sizes of this
buffer are 65535 and 0 respectively. Values outside this range are
rounded up or down appropriately.</
P>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
>Do not try the next server if you receive a SERVFAIL. The default is
to not try the next server which is the reverse of normal stub resolver
>Attempt to display the contents of messages which are malformed.
The default is to not display malformed answers.</
P>Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO)
in the OPT record in the additional section of the query.</
P>The BIND 9 implementation of <
Bspecifying multiple queries on the command line (in addition to
> batch file option). Each of those
queries can be supplied with its own set of flags, options and query
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.</
P>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
overridden by a query-specific set of query options. For example:
> could be used from the command line
to make three lookups: an ANY query for <
TTreverse lookup of 127.0.0.1 and a query for the NS records of
A global query option of <
TT> shows the initial query it made for each
lookup. The final query has a local query option of
will not print the initial query when it looks up the NS records for
>There are probably too many query options. </
P