1 .\" Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC")
2 .\" Copyright (C) 2000-2003 Internet Software Consortium.
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16 .\" $Id: dig.1,v 1.14.2.4.2.10 2005/10/13 02:33:42 marka Exp $
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24 .TH "DIG" "1" "Jun 30, 2000" "BIND9" "BIND9"
25 .\" disable hyphenation
27 .\" disable justification (adjust text to left margin only)
30 dig \- DNS lookup utility
33 \fBdig\fR [@server] [\fB\-b\ \fR\fB\fIaddress\fR\fR] [\fB\-c\ \fR\fB\fIclass\fR\fR] [\fB\-f\ \fR\fB\fIfilename\fR\fR] [\fB\-k\ \fR\fB\fIfilename\fR\fR] [\fB\-p\ \fR\fB\fIport#\fR\fR] [\fB\-t\ \fR\fB\fItype\fR\fR] [\fB\-x\ \fR\fB\fIaddr\fR\fR] [\fB\-y\ \fR\fB\fIname:key\fR\fR] [\fB\-4\fR] [\fB\-6\fR] [name] [type] [class] [queryopt...]
37 \fBdig\fR [global\-queryopt...] [query...]
41 (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
43 to troubleshoot DNS problems because of its flexibility, ease of use and clarity of output. Other lookup tools tend to have less functionality than
48 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
50 option is given. Unlike earlier versions, the BIND9 implementation of
52 allows multiple lookups to be issued from the command line.
54 Unless it is told to query a specific name server,
56 will try each of the servers listed in
57 \fI/etc/resolv.conf\fR.
59 When no command line arguments or options are given, will perform an NS query for "." (the root).
61 It is possible to set per\-user defaults for
64 \fI${HOME}/.digrc\fR. This file is read and any options in it are applied before the command line arguments.
67 A typical invocation of
78 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
80 argument is a hostname,
82 resolves that name before querying that name server. If no
87 \fI/etc/resolv.conf\fR
88 and queries the name servers listed there. The reply from the name server that responds is displayed.
91 is the name of the resource record that is to be looked up.
94 indicates what type of query is required \(em ANY, A, MX, SIG, etc.
96 can be any valid query type. If no
100 will perform a lookup for an A record.
105 option sets the source IP address of the query to
106 \fIaddress\fR. 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>"
108 The default query class (IN for internet) is overridden by the
112 is any valid class, such as HS for Hesiod records or CH for CHAOSNET records.
118 operate in batch mode by reading a list of lookup requests to process from the file
119 \fIfilename\fR. 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
121 using the command\-line interface.
123 If a non\-standard port number is to be queried, the
127 is the port number that
129 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.
135 to only use IPv4 query transport. The
139 to only use IPv6 query transport.
143 option sets the query type to
144 \fItype\fR. It can be any valid query type which is supported in BIND9. The default query type "A", unless the
146 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,
149 ixfr=N. The incremental zone transfer will contain the changes made to the zone since the serial number in the zone's SOA record was
152 Reverse lookups \- mapping addresses to names \- are simplified by the
156 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
163 automatically performs a lookup for a name like
164 11.12.13.10.in\-addr.arpa
165 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 specify the
167 option. Bit string labels (RFC2874) are now experimental and are not attempted.
169 To sign the DNS queries sent by
171 and their responses using transaction signatures (TSIG), specify a TSIG key file using the
173 option. You can also specify the TSIG key itself on the command line using the
177 is the name of the TSIG key and
179 is the actual key. The key is a base\-64 encoded string, typically generated by
180 \fBdnssec\-keygen\fR(8). Caution should be taken when using the
182 option on multi\-user systems as the key can be visible in the output from
184 or in the shell's history file. When using TSIG authentication with
185 \fBdig\fR, 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
194 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.
196 Each query option is identified by a keyword preceded by a plus sign (+). Some keywords set or reset an option. These may be preceded by the string
198 to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form
199 \fB+keyword=value\fR. The query options are:
202 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.
205 Use [do not use] TCP when querying name servers. This alternate syntax to
207 is provided for backwards compatibility. The "vc" stands for "virtual circuit".
210 Ignore truncation in UDP responses instead of retrying with TCP. By default, TCP retries are performed.
212 \fB+domain=somename\fR
213 Set the search list to contain the single domain
214 \fIsomename\fR, as if specified in a
217 \fI/etc/resolv.conf\fR, and enable search list processing as if the
222 Use [do not use] the search list defined by the searchlist or domain directive in
224 (if any). The search list is not used by default.
227 Deprecated, treated as a synonym for
231 Sets the "aa" flag in the query.
238 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.
241 Set [do not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses.
244 Display [do not display] the CLASS when printing the record.
247 Display [do not display] the TTL when printing the record.
250 Toggle the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means
252 normally sends recursive queries. Recursion is automatically disabled when the
256 query options are used.
259 When this option is set,
261 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.
264 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,
266 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.
269 toggles the printing of the initial comment in the output identifying the version of
271 and the query options that have been applied. This comment is printed by default.
274 Provide a terse answer. The default is to print the answer in a verbose form.
277 Show [or do not show] the IP address and port number that supplied the answer when the
279 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.
282 Toggle the display of comment lines in the output. The default is to print comments.
285 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.
288 Print [do not print] the query as it is sent. By default, the query is not printed.
291 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.
294 Display [do not display] the answer section of a reply. The default is to display it.
297 Display [do not display] the authority section of a reply. The default is to display it.
299 \fB+[no]additional\fR
300 Display [do not display] the additional section of a reply. The default is to display it.
303 Set or clear all display flags.
306 Sets the timeout for a query to
308 seconds. The default time out is 5 seconds. An attempt to set
310 to less than 1 will result in a query timeout of 1 second being applied.
313 Sets the number of times to try UDP queries to server to
315 instead of the default, 3. If
317 is less than or equal to zero, the number of tries is silently rounded up to 1.
320 Sets the number of times to retry UDP queries to server to
322 instead of the default, 2. Unlike
323 \fI+tries\fR, this does not include the initial query.
326 Set the number of dots that have to appear in
330 for it to be considered absolute. The default value is that defined using the ndots statement in
331 \fI/etc/resolv.conf\fR, 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
336 \fI/etc/resolv.conf\fR.
339 Set the UDP message buffer size advertised using EDNS0 to
341 bytes. The maximum and minimum sizes of this buffer are 65535 and 0 respectively. Values outside this range are rounded up or down appropriately.
344 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
349 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 behaviour.
351 \fB+[no]besteffort\fR
352 Attempt to display the contents of messages which are malformed. The default is to not display malformed answers.
355 Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO) in the OPT record in the additional section of the query.
358 Chase DNSSEC signature chains. Requires dig be compiled with \-DDIG_SIGCHASE.
360 \fB+trusted\-key=####\fR
361 Specifies a file containing trusted keys to be used with
362 \fB+sigchase\fR. Each DNSKEY record must be on its own line.
367 \fI/etc/trusted\-key.key\fR
369 \fItrusted\-key.key\fR
370 in the current directory.
372 Requires dig be compiled with \-DDIG_SIGCHASE.
375 When chasing DNSSEC signature chains perform a top down validation. Requires dig be compiled with \-DDIG_SIGCHASE.
376 .SH "MULTIPLE QUERIES"
378 The BIND 9 implementation of
380 supports specifying multiple queries on the command line (in addition to supporting the
382 batch file option). Each of those queries can be supplied with its own set of flags, options and query options.
386 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.
388 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
390 option) can be overridden by a query\-specific set of query options. For example:
393 dig +qr www.isc.org any \-x 127.0.0.1 isc.org ns +noqr
398 could be used from the command line to make three lookups: an ANY query for
399 www.isc.org, a reverse lookup of 127.0.0.1 and a query for the NS records of
400 isc.org. A global query option of
404 shows the initial query it made for each lookup. The final query has a local query option of
408 will not print the initial query when it looks up the NS records for
412 \fI/etc/resolv.conf\fR
419 \fBdnssec\-keygen\fR(8),
423 There are probably too many query options.