1DIG(1) BIND9 DIG(1)
2
6 dig - DNS lookup utility
7
9 dig [@server] [-b address] [-c class] [-f filename] [-k filename] [-m]
10 [-p port#] [-q name] [-t type] [-v] [-x addr] [-y [hmac:]name:key]
11 [[-4] | [-6]] [name] [type] [class] [queryopt...]
12 dig [-h]
14 dig [global-queryopt...] [query...]
16
18 dig is a flexible tool for interrogating DNS name servers. It performs
19 DNS lookups and displays the answers that are returned from the name
20 server(s) that were queried. Most DNS administrators use dig to
21 troubleshoot DNS problems because of its flexibility, ease of use and
22 clarity of output. Other lookup tools tend to have less functionality
23 than dig.
24 Although dig is normally used with command-line arguments, it also has
26 a batch mode of operation for reading lookup requests from a file. A
27 brief summary of its command-line arguments and options is printed when
28 the -h option is given. Unlike earlier versions, the BIND 9
29 implementation of dig allows multiple lookups to be issued from the
30 command line.
31 Unless it is told to query a specific name server, dig will try each of
33 the servers listed in /etc/resolv.conf. If no usable server addresses
34 are found, dig will send the query to the local host.
35 When no command line arguments or options are given, dig will perform
37 an NS query for "." (the root).
38 It is possible to set per-user defaults for dig via ${HOME}/.digrc.
40 This file is read and any options in it are applied before the command
41 line arguments.
42 The IN and CH class names overlap with the IN and CH top level domain
44 names. Either use the -t and -c options to specify the type and class,
45 use the -q the specify the domain name, or use "IN." and "CH." when
46 looking up these top level domains.
47
49 A typical invocation of dig looks like:
50 dig @server name type
52 where:
54 server
56 is the name or IP address of the name server to query. This can be
57 an IPv4 address in dotted-decimal notation or an IPv6 address in
58 colon-delimited notation. When the supplied server argument is a
59 hostname, dig resolves that name before querying that name server.
60 If no server argument is provided, dig consults /etc/resolv.conf;
62 if an address is found there, it queries the name server at that
63 address. If either of the -4 or -6 options are in use, then only
64 addresses for the corresponding transport will be tried. If no
65 usable addresses are found, dig will send the query to the local
66 host. The reply from the name server that responds is displayed.
67 name
69 is the name of the resource record that is to be looked up.
70 type
72 indicates what type of query is required — ANY, A, MX, SIG, etc.
73 type can be any valid query type. If no type argument is supplied,
74 dig will perform a lookup for an A record.
75
77 -4
78 Use IPv4 only.
79 -6
81 Use IPv6 only.
82 -b address[#port]
84 Set the source IP address of the query. The address must be a valid
85 address on one of the host's network interfaces, or "0.0.0.0" or
86 "::". An optional port may be specified by appending "#<port>"
87 -c class
89 Set the query class. The default class is IN; other classes are HS
90 for Hesiod records or CH for Chaosnet records.
91 -f file
93 Batch mode: dig reads a list of lookup requests to process from the
94 given file. Each line in the file should be organized in the same
95 way they would be presented as queries to dig using the
96 command-line interface.
97 -i
99 Do reverse IPv6 lookups using the obsolete RFC 1886 IP6.INT domain,
100 which is no longer in use. Obsolete bit string label queries (RFC
101 2874) are not attempted.
102 -k keyfile
104 Sign queries using TSIG using a key read from the given file. Key
105 files can be generated using tsig-keygen(8). When using TSIG
106 authentication with dig, the name server that is queried needs to
107 know the key and algorithm that is being used. In BIND, this is
108 done by providing appropriate key and server statements in
109 named.conf.
110 -m
112 Enable memory usage debugging.
113 -p port
115 Send the query to a non-standard port on the server, instead of the
116 default port 53. This option would be used to test a name server
117 that has been configured to listen for queries on a non-standard
118 port number.
119 -q name
121 The domain name to query. This is useful to distinguish the name
122 from other arguments.
123 -t type
125 The resource record type to query. It can be any valid query type.
126 If it is a resource record type supported in BIND 9, it can be
127 given by the type mnemonic (such as "NS" or "AAAA"). The default
128 query type is "A", unless the -x option is supplied to indicate a
129 reverse lookup. A zone transfer can be requested by specifying a
130 type of AXFR. When an incremental zone transfer (IXFR) is required,
131 set the type to ixfr=N. The incremental zone transfer will contain
132 the changes made to the zone since the serial number in the zone's
133 SOA record was N.
134 All resource record types can be expressed as "TYPEnn", where "nn"
136 is the number of the type. If the resource record type is not
137 supported in BIND 9, the result will be displayed as described in
138 RFC 3597.
139 -u
141 Print query times in microseconds instead of milliseconds.
142 -v
144 Print the version number and exit.
145 -x addr
147 Simplified reverse lookups, for mapping addresses to names. The
148 addr is an IPv4 address in dotted-decimal notation, or a
149 colon-delimited IPv6 address. When the -x is used, there is no need
150 to provide the name, class and type arguments. dig automatically
151 performs a lookup for a name like 94.2.0.192.in-addr.arpa and sets
152 the query type and class to PTR and IN respectively. IPv6 addresses
153 are looked up using nibble format under the IP6.ARPA domain (but
154 see also the -i option).
155 -y [hmac:]keyname:secret
157 Sign queries using TSIG with the given authentication key. keyname
158 is the name of the key, and secret is the base64 encoded shared
159 secret. hmac is the name of the key algorithm; valid choices are
160 hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, or
161 hmac-sha512. If hmac is not specified, the default is hmac-md5 or
162 if MD5 was disabled hmac-sha256.
163 NOTE: You should use the -k option and avoid the -y option, because
165 with -y the shared secret is supplied as a command line argument in
166 clear text. This may be visible in the output from ps(1) or in a
167 history file maintained by the user's shell.
168
170 dig provides a number of query options which affect the way in which
171 lookups are made and the results displayed. Some of these set or reset
172 flag bits in the query header, some determine which sections of the
173 answer get printed, and others determine the timeout and retry
174 strategies.
175 Each query option is identified by a keyword preceded by a plus sign
177 (+). Some keywords set or reset an option. These may be preceded by the
178 string no to negate the meaning of that keyword. Other keywords assign
179 values to options like the timeout interval. They have the form
180 +keyword=value. Keywords may be abbreviated, provided the abbreviation
181 is unambiguous; for example, +cd is equivalent to +cdflag. The query
182 options are:
183 +[no]aaflag
185 A synonym for +[no]aaonly.
186 +[no]aaonly
188 Sets the "aa" flag in the query.
189 +[no]additional
191 Display [do not display] the additional section of a reply. The
192 default is to display it.
193 +[no]adflag
195 Set [do not set] the AD (authentic data) bit in the query. This
196 requests the server to return whether all of the answer and
197 authority sections have all been validated as secure according to
198 the security policy of the server. AD=1 indicates that all records
199 have been validated as secure and the answer is not from a OPT-OUT
200 range. AD=0 indicate that some part of the answer was insecure or
201 not validated. This bit is set by default.
202 +[no]all
204 Set or clear all display flags.
205 +[no]answer
207 Display [do not display] the answer section of a reply. The default
208 is to display it.
209 +[no]authority
211 Display [do not display] the authority section of a reply. The
212 default is to display it.
213 +[no]badcookie
215 Retry lookup with the new server cookie if a BADCOOKIE response is
216 received.
217 +[no]besteffort
219 Attempt to display the contents of messages which are malformed.
220 The default is to not display malformed answers.
221 +bufsize=B
223 Set the UDP message buffer size advertised using EDNS0 to B bytes.
224 The maximum and minimum sizes of this buffer are 65535 and 0
225 respectively. Values outside this range are rounded up or down
226 appropriately. Values other than zero will cause a EDNS query to be
227 sent.
228 +[no]cdflag
230 Set [do not set] the CD (checking disabled) bit in the query. This
231 requests the server to not perform DNSSEC validation of responses.
232 +[no]class
234 Display [do not display] the CLASS when printing the record.
235 +[no]cmd
237 Toggles the printing of the initial comment in the output
238 identifying the version of dig and the query options that have been
239 applied. This comment is printed by default.
240 +[no]comments
242 Toggle the display of comment lines in the output. The default is
243 to print comments.
244 +[no]cookie[=####]
246 Send a COOKIE EDNS option, with optional value. Replaying a COOKIE
247 from a previous response will allow the server to identify a
248 previous client. The default is +cookie.
249 +cookie is also set when +trace is set to better emulate the
251 default queries from a nameserver.
252 +[no]crypto
254 Toggle the display of cryptographic fields in DNSSEC records. The
255 contents of these field are unnecessary to debug most DNSSEC
256 validation failures and removing them makes it easier to see the
257 common failures. The default is to display the fields. When omitted
258 they are replaced by the string "[omitted]" or in the DNSKEY case
259 the key id is displayed as the replacement, e.g. "[ key id = value
260 ]".
261 +[no]defname
263 Deprecated, treated as a synonym for +[no]search
264 +[no]dnssec
266 Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO)
267 in the OPT record in the additional section of the query.
268 +domain=somename
270 Set the search list to contain the single domain somename, as if
271 specified in a domain directive in /etc/resolv.conf, and enable
272 search list processing as if the +search option were given.
273 +dscp=value
275 Set the DSCP code point to be used when sending the query. Valid
276 DSCP code points are in the range [0..63]. By default no code point
277 is explicitly set.
278 +[no]edns[=#]
280 Specify the EDNS version to query with. Valid values are 0 to 255.
281 Setting the EDNS version will cause a EDNS query to be sent.
282 +noedns clears the remembered EDNS version. EDNS is set to 0 by
283 default.
284 +[no]ednsflags[=#]
286 Set the must-be-zero EDNS flags bits (Z bits) to the specified
287 value. Decimal, hex and octal encodings are accepted. Setting a
288 named flag (e.g. DO) will silently be ignored. By default, no Z
289 bits are set.
290 +[no]ednsnegotiation
292 Enable / disable EDNS version negotiation. By default EDNS version
293 negotiation is enabled.
294 +[no]ednsopt[=code[:value]]
296 Specify EDNS option with code point code and optionally payload of
297 value as a hexadecimal string. code can be either an EDNS option
298 name (for example, NSID or ECS), or an arbitrary numeric value.
299 +noednsopt clears the EDNS options to be sent.
300 +[no]expire
302 Send an EDNS Expire option.
303 +[no]fail
305 Do not try the next server if you receive a SERVFAIL. The default
306 is to not try the next server which is the reverse of normal stub
307 resolver behavior.
308 +[no]header-only
310 Send a query with a DNS header without a question section. The
311 default is to add a question section. The query type and query name
312 are ignored when this is set.
313 +[no]identify
315 Show [or do not show] the IP address and port number that supplied
316 the answer when the +short option is enabled. If short form answers
317 are requested, the default is not to show the source address and
318 port number of the server that provided the answer.
319 +[no]idnin
321 Process [do not process] IDN domain names on input. This requires
322 IDN SUPPORT to have been enabled at compile time. The default is to
323 process IDN input.
324 +[no]idnout
326 Convert [do not convert] puny code on output. This requires IDN
327 SUPPORT to have been enabled at compile time. The default is to
328 convert output.
329 +[no]ignore
331 Ignore truncation in UDP responses instead of retrying with TCP. By
332 default, TCP retries are performed.
333 +[no]keepopen
335 Keep the TCP socket open between queries and reuse it rather than
336 creating a new TCP socket for each lookup. The default is
337 +nokeepopen.
338 +[no]mapped
340 Allow mapped IPv4 over IPv6 addresses to be used. The default is
341 +mapped.
342 +[no]multiline
344 Print records like the SOA records in a verbose multi-line format
345 with human-readable comments. The default is to print each record
346 on a single line, to facilitate machine parsing of the dig output.
347 +ndots=D
349 Set the number of dots that have to appear in name to D for it to
350 be considered absolute. The default value is that defined using the
351 ndots statement in /etc/resolv.conf, or 1 if no ndots statement is
352 present. Names with fewer dots are interpreted as relative names
353 and will be searched for in the domains listed in the search or
354 domain directive in /etc/resolv.conf if +search is set.
355 +[no]nsid
357 Include an EDNS name server ID request when sending a query.
358 +[no]nssearch
360 When this option is set, dig attempts to find the authoritative
361 name servers for the zone containing the name being looked up and
362 display the SOA record that each name server has for the zone.
363 +[no]onesoa
365 Print only one (starting) SOA record when performing an AXFR. The
366 default is to print both the starting and ending SOA records.
367 +[no]opcode=value
369 Set [restore] the DNS message opcode to the specified value. The
370 default value is QUERY (0).
371 +[no]qr
373 Print [do not print] the query as it is sent. By default, the query
374 is not printed.
375 +[no]question
377 Print [do not print] the question section of a query when an answer
378 is returned. The default is to print the question section as a
379 comment.
380 +[no]rdflag
382 A synonym for +[no]recurse.
383 +[no]recurse
385 Toggle the setting of the RD (recursion desired) bit in the query.
386 This bit is set by default, which means dig normally sends
387 recursive queries. Recursion is automatically disabled when the
388 +nssearch or +trace query options are used.
389 +retry=T
391 Sets the number of times to retry UDP queries to server to T
392 instead of the default, 2. Unlike +tries, this does not include the
393 initial query.
394 +[no]rrcomments
396 Toggle the display of per-record comments in the output (for
397 example, human-readable key information about DNSKEY records). The
398 default is not to print record comments unless multiline mode is
399 active.
400 +[no]search
402 Use [do not use] the search list defined by the searchlist or
403 domain directive in resolv.conf (if any). The search list is not
404 used by default.
405 'ndots' from resolv.conf (default 1) which may be overridden by
407 +ndots determines if the name will be treated as relative or not
408 and hence whether a search is eventually performed or not.
409 +[no]short
411 Provide a terse answer. The default is to print the answer in a
412 verbose form.
413 +[no]showsearch
415 Perform [do not perform] a search showing intermediate results.
416 +[no]sigchase
418 Chase DNSSEC signature chains. Requires dig be compiled with
419 -DDIG_SIGCHASE. This feature is deprecated. Use delv instead.
420 +split=W
422 Split long hex- or base64-formatted fields in resource records into
423 chunks of W characters (where W is rounded up to the nearest
424 multiple of 4). +nosplit or +split=0 causes fields not to be split
425 at all. The default is 56 characters, or 44 characters when
426 multiline mode is active.
427 +[no]stats
429 This query option toggles the printing of statistics: when the
430 query was made, the size of the reply and so on. The default
431 behavior is to print the query statistics.
432 +[no]subnet=addr[/prefix-length]
434 Send (don't send) an EDNS Client Subnet option with the specified
435 IP address or network prefix.
436 dig +subnet=0.0.0.0/0, or simply dig +subnet=0 for short, sends an
438 EDNS CLIENT-SUBNET option with an empty address and a source
439 prefix-length of zero, which signals a resolver that the client's
440 address information must not be used when resolving this query.
441 +[no]tcp
443 Use [do not use] TCP when querying name servers. The default
444 behavior is to use UDP unless a type any or ixfr=N query is
445 requested, in which case the default is TCP. AXFR queries always
446 use TCP.
447 +timeout=T
449 Sets the timeout for a query to T seconds. The default timeout is 5
450 seconds. An attempt to set T to less than 1 will result in a query
451 timeout of 1 second being applied.
452 +[no]topdown
454 When chasing DNSSEC signature chains perform a top-down validation.
455 Requires dig be compiled with -DDIG_SIGCHASE. This feature is
456 deprecated. Use delv instead.
457 +[no]trace
459 Toggle tracing of the delegation path from the root name servers
460 for the name being looked up. Tracing is disabled by default. When
461 tracing is enabled, dig makes iterative queries to resolve the name
462 being looked up. It will follow referrals from the root servers,
463 showing the answer from each server that was used to resolve the
464 lookup.
465 If @server is also specified, it affects only the initial query for
467 the root zone name servers.
468 +dnssec is also set when +trace is set to better emulate the
470 default queries from a nameserver.
471 +tries=T
473 Sets the number of times to try UDP queries to server to T instead
474 of the default, 3. If T is less than or equal to zero, the number
475 of tries is silently rounded up to 1.
476 +trusted-key=####
478 Specifies a file containing trusted keys to be used with +sigchase.
479 Each DNSKEY record must be on its own line.
480 If not specified, dig will look for /etc/trusted-key.key then
482 trusted-key.key in the current directory.
483 Requires dig be compiled with -DDIG_SIGCHASE. This feature is
485 deprecated. Use delv instead.
486 +[no]ttlid
488 Display [do not display] the TTL when printing the record.
489 +[no]ttlunits
491 Display [do not display] the TTL in friendly human-readable time
492 units of "s", "m", "h", "d", and "w", representing seconds,
493 minutes, hours, days and weeks. Implies +ttlid.
494 +[no]unknownformat
496 Print all RDATA in unknown RR type presentation format (RFC 3597).
497 The default is to print RDATA for known types in the type's
498 presentation format.
499 +[no]vc
501 Use [do not use] TCP when querying name servers. This alternate
502 syntax to +[no]tcp is provided for backwards compatibility. The
503 "vc" stands for "virtual circuit".
504 +[no]zflag
506 Set [do not set] the last unassigned DNS header flag in a DNS
507 query. This flag is off by default.
508
510 The BIND 9 implementation of dig supports specifying multiple queries
511 on the command line (in addition to supporting the -f batch file
512 option). Each of those queries can be supplied with its own set of
513 flags, options and query options.
514 In this case, each query argument represent an individual query in the
516 command-line syntax described above. Each consists of any of the
517 standard options and flags, the name to be looked up, an optional query
518 type and class and any query options that should be applied to that
519 query.
520 A global set of query options, which should be applied to all queries,
522 can also be supplied. These global query options must precede the first
523 tuple of name, class, type, options, flags, and query options supplied
524 on the command line. Any global query options (except the +[no]cmd
525 option) can be overridden by a query-specific set of query options. For
526 example:
527 dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr
529 shows how dig could be used from the command line to make three
531 lookups: an ANY query for www.isc.org, a reverse lookup of 127.0.0.1
532 and a query for the NS records of isc.org. A global query option of +qr
533 is applied, so that dig shows the initial query it made for each
534 lookup. The final query has a local query option of +noqr which means
535 that dig will not print the initial query when it looks up the NS
536 records for isc.org.
537
539 If dig has been built with IDN (internationalized domain name) support,
540 it can accept and display non-ASCII domain names. dig appropriately
541 converts character encoding of domain name before sending a request to
542 DNS server or displaying a reply from the server. If you'd like to turn
543 off the IDN support for some reason, use parameters +noidnin and
544 +noidnout or define the IDN_DISABLE environment variable.
545
547 Dig return codes are:
548 0: Everything went well, including things like NXDOMAIN
550 1: Usage error
552 8: Couldn't open batch file
554 9: No reply from server
556 10: Internal error
558
560 /etc/resolv.conf
561 ${HOME}/.digrc
563
565 delv(1), host(1), named(8), dnssec-keygen(8), RFC 1035.
566
568 There are probably too many query options.
569
571 Internet Systems Consortium, Inc.
572
574 Copyright © 2000-2011, 2013-2018 Internet Systems Consortium, Inc.
575 ("ISC")
576ISC 2014-02-19 DIG(1)