System Administration Commands dig(1M)
NAME
dig - DNS lookup utility
SYNOPSIS
dig [@server] [-b address] [-c class] [-f filename]
[-k filename] [-m] [-p port#] [-q name] [-t type] [-x addr]
[-y [hmac:]name:key] [-4] [-6] [name] [type] [class] [queryopt]...
dig [-h]
dig [global-queryopt...] [query...]
DESCRIPTION
The dig utility (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 administratorsuse dig to troubleshoot DNS problems because of its flexi-
bility, ease of use and clarity of output. Other lookuptools tend to have less functionality than dig.
Although dig is normally used with command-line arguments,
it also has a batch mode of operation for reading lookuprequests from a file. A brief summary of its command-line
arguments and options is printed when the -h option is
specified. Unlike earlier versions, the BIND 9 implementa-
tion of dig allows multiple lookups to be issued from the
command line.Unless it is told to query a specific name server, dig tries
each of the servers listed in /etc/resolv.conf.When no command line arguments or options are given, dig
performs an NS query for "." (the root).It is possible to set per-user defaults for dig with
${HOME}/.digrc. This file is read and any options in it are
applied before the command line arguments. The IN and CH class names overlap with the IN and CH toplevel domains names. Either use the -t and -c options to
specify the type and class, or use "IN." and "CH." when looking up these top level domains.SunOS 5.11 Last change: 11 Jan 2010 1
System Administration Commands dig(1M)
Simple UsageThe following is a typical invocation of dig:
dig @server name type
where: server The name or IP address of the name server to query. Thiscan be an IPv4 address in dotted-decimal notation or an
IPv6 address in colon-delimited notation. When the sup-
plied server argument is a hostname, dig resolves that
name before querying that name server. If no serverargument is provided, dig consults /etc/resolv.conf and
queries the name servers listed there. The reply from the name server that responds is displayed. name The name of the resource record that is to be looked up. type Indicates what type of query is required (ANY, A, MX, SIG, among others.) type can be any valid query type. Ifno type argument is supplied, dig performs a lookup for
an A record. OPTIONS The following options are supported:-4
Use only IPv4 transport. By default both IPv4 and IPv6transports can be used. Options -4 and -6 are mutually
exclusive.-6
Use only IPv6 transport. By default both IPv4 and IPv6transports can be used. Options -4 and -6 are mutually
exclusive.SunOS 5.11 Last change: 11 Jan 2010 2
System Administration Commands dig(1M)
-b address
Set the source IP address of the query to address. This must be a valid address on one of the host's network interfaces or 0.0.0.0 or ::. An optional port may bespecified by appending: #
-c class
Override the default query class (IN for internet). The class argument is any valid class, such as HS for Hesiod records or CH for CHAOSNET records.-f filename
Operate in batch mode by reading a list of lookup requests to process from the file filename. The file contains a number of queries, one per line. Each entry in the file should be organized in the same way theywould be presented as queries to dig using the command-
line interface.-h
Print a brief summary of command-line arguments and
options.-k filename
Specify a transaction signature (TSIG) key file to signthe DNS queries sent by dig and their responses using
TSIGs.-m
Enable memory usage debugging.-p port#
Query a non-standard port number. The port# argument is
the port number that dig sends its queries instead of
the standard DNS port number 53. This option tests a name server that has been configured to listen forqueries on a non-standard port number.
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System Administration Commands dig(1M)
-q name
Sets the query name to name. This can be useful in that the query name can be easily distinguished from other arguments.-t type
Set the query type to type, which can be any valid query type supported in BIND9. The default query type "A",unless the -x 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, type is set to 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 N.-x addr
Simplify reverse lookups (mapping addresses to names ).The addr argument 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 name,class and type arguments. The dig utility automatically
performs a lookup for a name like 11.12.13.10.in-
addr.arpa 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 -i option. Bit string labels (RFC 2874) are
now experimental and are not attempted.-y [hmac:]name:key
Specify a transaction signature (TSIG) key on the com-
mand line. This is done to sign the DNS queries sent bydig, as well as their responses. You can also specify
the TSIG key itself on the command line using the -y
option. The optional hmac is the type of TSIG; thedefault is HMAC-MD5. The name argument is the name of
the TSIG key and the key argument is the actual key. Thekey is a base-64 encoded string, typically generated by
dnssec-keygen(1M).
Caution should be taken when using the -y option on
multi-user systems, since the key can be visible in the
output from ps(1) or in the shell's history file. Whenusing TSIG authentication with dig, the name server that
is queried needs to know the key and algorithm that isSunOS 5.11 Last change: 11 Jan 2010 4
System Administration Commands dig(1M)
being used. In BIND, this is done by providing appropri-
ate key and server statements in named.conf. QUERY OPTIONSThe dig utility 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 getprinted, and others determine the timeout and retry stra-
tegies. 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 no to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form +keyword=value. The query options are: +[no]tcp 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. +[no]vc Use [do not use] TCP when querying name servers. This alternate syntax to +[no]tcp is provided for backwards compatibility. The "vc" stands for "virtual circuit". +[no]ignore Ignore truncation in UDP responses instead of retrying with TCP. By default, TCP retries are performed. +domain=somename Set the search list to contain the single domain somename, as if specified in a domain directive in /etc/resolv.conf, and enable search list processing as if the +search option were given. +[no]search Use [do not use] the search list defined by theSunOS 5.11 Last change: 11 Jan 2010 5
System Administration Commands dig(1M)
searchlist or domain directive in resolv.conf (if any). The search list is not used by default. +[no]showsearch Perform [do not perform] a search showing intermediate results. +[no]defname Deprecated, treated as a synonym for +[no]search. +[no]aaonly Sets the aa flag in the query. +[no]aaflag A synonym for +[no]aaonly. +[no]adflag Set [do not set] the AD (authentic data) bit in the query. This requests that the server return, regardless of whether all of the answer and authority sections have all been validated as secure according to the security policy of the server. A setting of AD=1 indicates that all records have been validated as secure and the answeris not from an OPT-OUT range. AD=0 indicates that some
part of the answer is insecure or not validated. +[no]cdflag Set [do not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses. +[no]cl Display [do not display] the CLASS when printing the record. +[no]ttlidSunOS 5.11 Last change: 11 Jan 2010 6
System Administration Commands dig(1M)
Display [do not display] the TTL when printing the record. +[no]recurse Toggle the setting of the RD (recursion desired) bit inthe query. This bit is set by default, which means dig
normally sends recursive queries. Recursion is automati-
cally disabled when the +nssearch or +trace query options are used. +[no]nssearchWhen this option is set, dig 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. +[no]trace Toggle tracing of the delegation path from the root nameservers for the name being looked up. Tracing is dis-
abled by default. When tracing is enabled, dig 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. +[no]cmd Toggle the printing of the initial comment in the outputidentifying the version of dig and the query options
that have been applied. This comment is printed by default. +[no]short Provide a terse answer. The default is to print the answer in a verbose form. +[no]identify Show [or do not show] the IP address and port number that supplied the answer when the +short option is enabled. If short form answers are requested, the default is not to show the source address and portSunOS 5.11 Last change: 11 Jan 2010 7
System Administration Commands dig(1M)
number of the server that provided the answer. +[no]comments Toggle the display of comment lines in the output. The default is to print comments. +[no]stats Toggle 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. +[no]qr Print [do not print] the query as it is sent. By default, the query is not printed. +[no]question 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. +[no]answer Display [do not display] the answer section of a reply. The default is to display it. +[no]authority Display [do not display] the authority section of a reply. The default is to display it. +[no]additional Display [do not display] the additional section of a reply. The default is to display it. +[no]all Set or clear all display flags.SunOS 5.11 Last change: 11 Jan 2010 8
System Administration Commands dig(1M)
+time=T Sets the timeout for a query to T seconds. The default time out is 5 seconds. An attempt to set T to less than 1 will result in a query timeout of 1 second being applied. +tries=T Sets the maximum number of UDP attempts to T. The default number is 3 (1 initial attempt followed by 2 retries). If T is less than or equal to zero, the number of retries is silently rounded up to 1. +retry=T Sets the number of UDP retries to T. The default is 2. +ndots=D Set the number of dots that have to appear in name to D for it to be considered absolute. The default value is that defined using the ndots statement in /etc/resolv.conf, 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 search or domain directive in /etc/resolv.conf. +bufsize=B Set the UDP message buffer size advertised using EDNS0 to B bytes. The maximum and minimum sizes of this buffer are 65535 and 0 respectively. Values outside this range are rounded up or down appropriately.+edns=#
Specify the EDNS version with which to query. Valid values are 0 to 255. Setting the EDNS version causes a EDNS query to be sent. +noedns clears the remembered EDNS version. +[no]multilinePrint records like the SOA records in a verbose multi-
line format with human-readable comments. The default is
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System Administration Commands dig(1M)
to print each record on a single line, to facilitatemachine parsing of the dig output.
+[no]fail 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. +[no]besteffort Attempt to display the contents of messages which are malformed. The default is to not display malformed answers. +[no]dnssec Request DNSSEC records be sent by setting the DNSSEC OK bit (DO) in the OPT record in the additional section of the query. +[no]sigchaseChase DNSSEC signature chains. Requires dig be compiled
with -DDIG_SIGCHASE.
+trusted-key=####
Specifies a file containing trusted keys to be used with +sigchase. Each DNSKEY record must be on its own line.If not specified dig will look for /etc/trusted-key.key
then trusted-key.key in the current directory.
Requires dig be compiled with -DDIG_SIGCHASE.
+[no]topdownWhen chasing DNSSEC signature chains, perform a top-down
validation. Requires dig be compiled with
-DDIG_SIGCHASE.
+[no]nsid Include an EDNS name server ID request when sending aSunOS 5.11 Last change: 11 Jan 2010 10
System Administration Commands dig(1M)
query. MULTIPLE QUERIESThe BIND 9 implementation of dig supports specifying multi-
ple queries on the command line (in addition to supportingthe -f batch file option). Each of those queries can be sup-
plied with its own set of flags, options and query options. In this case, each query argument represent an individualquery in the command-line syntax described above. Each con-
sists 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. 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 +[no]cmd option)can be overridden by a query-specific set of query options.
For example:dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr
...shows how dig could be used from the command line to make
three lookups: an ANY query for www.isc.org, a reverse lookup of 127.0.0.1 and a query for the NS records of isc.org. A global query option of +qr is applied, so thatdig shows the initial query it made for each lookup. The
final query has a local query option of +noqr which meansthat dig will not print the initial query when it looks up
the NS records for isc.org. FILES /etc/resolv.conf Resolver configuration file${HOME}/.digrc
User-defined configuration file
ATTRIBUTES
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System Administration Commands dig(1M)
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | network/dns/bind ||_____________________________|_____________________________|
| Interface Stability | Volatile ||_____________________________|_____________________________|
SEE ALSO
dnssec-keygen(1M), host(1M), named(1M), nslookup(1M), attri-
butes(5) RFC 1035 See the BIND 9 Administrator's Reference Manual. As of the date of publication of this man page, this document is available at https://www.isc.org/software/bind/documentation.BUGS
There are probably too many query options. NOTESnslookup(1M) and dig now report "Not Implemented" as NOTIMP
rather than NOTIMPL. This will have impact on scripts that are looking for NOTIMPL.SunOS 5.11 Last change: 11 Jan 2010 12