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24 .\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
25 .\" Date: February 19, 2014
29 .TH "DIG" "1" "February 19, 2014" "BIND9" "BIND9"
30 .\" disable hyphenation
32 .\" disable justification (adjust text to left margin only)
35 dig \- DNS lookup utility
38 \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\-m\fR] [\fB\-p\ \fR\fB\fIport#\fR\fR] [\fB\-q\ \fR\fB\fIname\fR\fR] [\fB\-t\ \fR\fB\fItype\fR\fR] [\fB\-v\fR] [\fB\-x\ \fR\fB\fIaddr\fR\fR] [\fB\-y\ \fR\fB\fI[hmac:]\fR\fIname:key\fR\fR] [\fB\-4\fR] [\fB\-6\fR] [name] [type] [class] [queryopt...]
42 \fBdig\fR [global\-queryopt...] [query...]
46 (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
48 to troubleshoot DNS problems because of its flexibility, ease of use and clarity of output. Other lookup tools tend to have less functionality than
53 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
55 option is given. Unlike earlier versions, the BIND 9 implementation of
57 allows multiple lookups to be issued from the command line.
59 Unless it is told to query a specific name server,
61 will try each of the servers listed in
62 \fI/etc/resolv.conf\fR. If no usable server addresses are found,
64 will send the query to the local host.
66 When no command line arguments or options are given,
68 will perform an NS query for "." (the root).
70 It is possible to set per\-user defaults for
73 \fI${HOME}/.digrc\fR. This file is read and any options in it are applied before the command line arguments.
75 The IN and CH class names overlap with the IN and CH top level domain names. Either use the
79 options to specify the type and class, use the
81 the specify the domain name, or use "IN." and "CH." when looking up these top level domains.
84 A typical invocation of
98 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
100 argument is a hostname,
102 resolves that name before querying that name server.
106 argument is provided,
109 \fI/etc/resolv.conf\fR; if an address is found there, it queries the name server at that address. If either of the
113 options are in use, then only addresses for the corresponding transport will be tried. If no usable addresses are found,
115 will send the query to the local host. The reply from the name server that responds is displayed.
120 is the name of the resource record that is to be looked up.
125 indicates what type of query is required \(em ANY, A, MX, SIG, etc.
127 can be any valid query type. If no
129 argument is supplied,
131 will perform a lookup for an A record.
137 option sets the source IP address of the query to
138 \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>"
140 The default query class (IN for internet) is overridden by the
144 is any valid class, such as HS for Hesiod records or CH for Chaosnet records.
150 operate in batch mode by reading a list of lookup requests to process from the file
151 \fIfilename\fR. The file contains a number of queries, one per line. Each entry in the file should be organized in the same way they would be presented as queries to
153 using the command\-line interface.
157 option enables memory usage debugging.
159 If a non\-standard port number is to be queried, the
163 is the port number that
165 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.
171 to only use IPv4 query transport. The
175 to only use IPv6 query transport.
179 option sets the query type to
180 \fItype\fR. It can be any valid query type which is supported in BIND 9. The default query type is "A", unless the
182 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,
185 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
190 option sets the query name to
191 \fIname\fR. This is useful to distinguish the
193 from other arguments.
199 to print the version number and exit.
201 Reverse lookups \(em mapping addresses to names \(em are simplified by the
205 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
212 automatically performs a lookup for a name like
213 11.12.13.10.in\-addr.arpa
214 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
216 option. Bit string labels (RFC2874) are now experimental and are not attempted.
218 To sign the DNS queries sent by
220 and their responses using transaction signatures (TSIG), specify a TSIG key file using the
222 option. You can also specify the TSIG key itself on the command line using the
226 is the type of the TSIG, default HMAC\-MD5,
228 is the name of the TSIG key and
230 is the actual key. The key is a base\-64 encoded string, typically generated by
231 \fBdnssec\-keygen\fR(8). Caution should be taken when using the
233 option on multi\-user systems as the key can be visible in the output from
235 or in the shell's history file. When using TSIG authentication with
236 \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
245 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.
247 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
249 to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form
250 \fB+keyword=value\fR. The query options are:
260 Sets the "aa" flag in the query.
263 \fB+[no]additional\fR
265 Display [do not display] the additional section of a reply. The default is to display it.
270 Set [do not set] the AD (authentic data) bit in the query. This requests the server to return whether all of the answer and authority sections have all been validated as secure according to the security policy of the server. AD=1 indicates that all records have been validated as secure and the answer is not from a OPT\-OUT range. AD=0 indicate that some part of the answer was insecure or not validated. This bit is set by default.
275 Set or clear all display flags.
280 Display [do not display] the answer section of a reply. The default is to display it.
285 Display [do not display] the authority section of a reply. The default is to display it.
288 \fB+[no]besteffort\fR
290 Attempt to display the contents of messages which are malformed. The default is to not display malformed answers.
295 Set the UDP message buffer size advertised using EDNS0 to
297 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.
302 Set [do not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses.
307 Display [do not display] the CLASS when printing the record.
312 Toggles the printing of the initial comment in the output identifying the version of
314 and the query options that have been applied. This comment is printed by default.
319 Toggle the display of comment lines in the output. The default is to print comments.
324 Toggle the display of cryptographic fields in DNSSEC records. The contents of these field are unnecessary to debug most DNSSEC validation failures and removing them makes it easier to see the common failures. The default is to display the fields. When omitted they are replaced by the string "[omitted]" or in the DNSKEY case the key id is displayed as the replacement, e.g. "[ key id = value ]".
329 Deprecated, treated as a synonym for
335 Requests DNSSEC records be sent by setting the DNSSEC OK bit (DO) in the OPT record in the additional section of the query.
338 \fB+domain=somename\fR
340 Set the search list to contain the single domain
341 \fIsomename\fR, as if specified in a
344 \fI/etc/resolv.conf\fR, and enable search list processing as if the
351 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.
353 clears the remembered EDNS version. EDNS is set to 0 by default.
358 Send an EDNS Expire option.
363 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 behavior.
368 Show [or do not show] the IP address and port number that supplied the answer when the
370 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.
375 Ignore truncation in UDP responses instead of retrying with TCP. By default, TCP retries are performed.
380 Keep the TCP socket open between queries and reuse it rather than creating a new TCP socket for each lookup. The default is
386 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
393 Set the number of dots that have to appear in
397 for it to be considered absolute. The default value is that defined using the ndots statement in
398 \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
403 \fI/etc/resolv.conf\fR
411 Include an EDNS name server ID request when sending a query.
416 When this option is set,
418 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.
423 Print only one (starting) SOA record when performing an AXFR. The default is to print both the starting and ending SOA records.
428 Print [do not print] the query as it is sent. By default, the query is not printed.
433 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.
438 Toggle the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means
440 normally sends recursive queries. Recursion is automatically disabled when the
444 query options are used.
449 Sets the number of times to retry UDP queries to server to
451 instead of the default, 2. Unlike
452 \fI+tries\fR, this does not include the initial query.
455 \fB+[no]rrcomments\fR
457 Toggle the display of per\-record comments in the output (for example, human\-readable key information about DNSKEY records). The default is not to print record comments unless multiline mode is active.
462 Use [do not use] the search list defined by the searchlist or domain directive in
464 (if any). The search list is not used by default.
468 (default 1) which may be overridden by
470 determines if the name will be treated as relative or not and hence whether a search is eventually performed or not.
475 Provide a terse answer. The default is to print the answer in a verbose form.
478 \fB+[no]showsearch\fR
480 Perform [do not perform] a search showing intermediate results.
485 Chase DNSSEC signature chains. Requires dig be compiled with \-DDIG_SIGCHASE.
488 \fB+[no]sit\fR\fB[=####]\fR
490 Send a Source Identity Token EDNS option, with optional value. Replaying a SIT from a previous response will allow the server to identify a previous client. The default is
491 \fB+nosit\fR. Currently using experimental value 65001 for the option code.
496 Split long hex\- or base64\-formatted fields in resource records into chunks of
500 is rounded up to the nearest multiple of 4).
504 causes fields not to be split at all. The default is 56 characters, or 44 characters when multiline mode is active.
509 This query option toggles the printing of statistics: when the query was made, the size of the reply and so on. The default behavior is to print the query statistics.
512 \fB+[no]subnet=addr/prefix\fR
514 Send an EDNS Client Subnet option with the specified IP address or network prefix.
519 Use [do not use] TCP when querying name servers. The default behavior is to use UDP unless an
521 query is requested, in which case the default is TCP. AXFR queries always use TCP.
526 Sets the timeout for a query to
528 seconds. The default timeout is 5 seconds. An attempt to set
530 to less than 1 will result in a query timeout of 1 second being applied.
535 When chasing DNSSEC signature chains perform a top\-down validation. Requires dig be compiled with \-DDIG_SIGCHASE.
540 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,
542 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.
545 is also set when +trace is set to better emulate the default queries from a nameserver.
550 Sets the number of times to try UDP queries to server to
552 instead of the default, 3. If
554 is less than or equal to zero, the number of tries is silently rounded up to 1.
557 \fB+trusted\-key=####\fR
559 Specifies a file containing trusted keys to be used with
560 \fB+sigchase\fR. Each DNSKEY record must be on its own line.
565 \fI/etc/trusted\-key.key\fR
567 \fItrusted\-key.key\fR
568 in the current directory.
570 Requires dig be compiled with \-DDIG_SIGCHASE.
575 Display [do not display] the TTL when printing the record.
580 Use [do not use] TCP when querying name servers. This alternate syntax to
582 is provided for backwards compatibility. The "vc" stands for "virtual circuit".
584 .SH "MULTIPLE QUERIES"
586 The BIND 9 implementation of
588 supports specifying multiple queries on the command line (in addition to supporting the
590 batch file option). Each of those queries can be supplied with its own set of flags, options and query options.
594 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.
596 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
598 option) can be overridden by a query\-specific set of query options. For example:
602 dig +qr www.isc.org any \-x 127.0.0.1 isc.org ns +noqr
608 could be used from the command line to make three lookups: an ANY query for
609 www.isc.org, a reverse lookup of 127.0.0.1 and a query for the NS records of
610 isc.org. A global query option of
614 shows the initial query it made for each lookup. The final query has a local query option of
618 will not print the initial query when it looks up the NS records for
624 has been built with IDN (internationalized domain name) support, it can accept and display non\-ASCII domain names.
626 appropriately converts character encoding of domain name before sending a request to DNS server or displaying a reply from the server. If you'd like to turn off the IDN support for some reason, defines the
628 environment variable. The IDN support is disabled if the variable is set when
633 \fI/etc/resolv.conf\fR
640 \fBdnssec\-keygen\fR(8),
644 There are probably too many query options.
646 Copyright \(co 2004\-2011, 2013, 2014 Internet Systems Consortium, Inc. ("ISC")
648 Copyright \(co 2000\-2003 Internet Software Consortium.