dig(1M) System Administration Commands dig(1M)NAMEdig - DNS lookup utility
SYNOPSISdig [@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 administrators use dig to troubleshoot DNS problems
because of its flexibility, ease of use and clarity of output. Other
lookup tools 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 lookup requests 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 imple‐
mentation 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 top level 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.
Simple Usage
The following is a typical invocation of dig:
dig @server name type
where:
server
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 server argument is a
hostname, dig resolves that name before querying that name server.
If no server argument 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. If no 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 IPv6 transports
can be used. Options -4 and -6 are mutually exclusive.
-6
Use only IPv6 transport. By default both IPv4 and IPv6 transports
can be used. Options -4 and -6 are mutually exclusive.
-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 be specified by appending: #<port>
-c class
Override the default query class (IN for internet). The class argu‐
ment 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 they would 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 sign the 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 for queries on a non-standard port number.
-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 sup‐
ported 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, respec‐
tively. By default, IPv6 addresses are looked up using nibble for‐
mat 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 command line.
This is done to sign the DNS queries sent by dig, 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;
the default is HMAC-MD5. The name argument is the name of the TSIG
key and the key argument is the actual key. The key is a base-64
encoded string, typically generated by dnssec-keygen(1M).
Caution should be taken when using the -y option on multi-user sys‐
tems, since the key can be visible in the output from ps(1) or in
the shell's history file. When using TSIG authentication with dig,
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
key and server statements in named.conf.
QUERY OPTIONS
The 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 get printed, and others determine the timeout and retry
strategies.
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 +key‐
word=value. The query options are:
+[no]tcp
Use [do not use] TCP when querying name servers. The default behav‐
iour 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 the 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
answer is 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]ttlid
Display [do not display] the TTL when printing the record.
+[no]recurse
Toggle the setting of the RD (recursion desired) bit in the query.
This bit is set by default, which means dig normally sends recur‐
sive queries. Recursion is automatically disabled when the
+nssearch or +trace query options are used.
+[no]nssearch
When 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 name servers
for the name being looked up. Tracing is disabled 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 output identify‐
ing 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
port 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 com‐
ment.
+[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.
+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]multiline
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 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]sigchase
Chase 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]topdown
When chasing DNSSEC signature chains, perform a top-down valida‐
tion. Requires dig be compiled with -DDIG_SIGCHASE.
+[no]nsid
Include an EDNS name server ID request when sending a query.
MULTIPLE QUERIES
The BIND 9 implementation of dig supports specifying multiple queries
on the command line (in addition to supporting the -f batch file
option). Each of those queries can be supplied with its own set of
flags, options and query options.
In this case, each query argument represent an individual query in the
command-line syntax described above. Each consists of any of the stan‐
dard 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 that dig shows the initial query it made for each
lookup. The final query has a local query option of +noqr which means
that 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
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │network/dns/bind │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOdnssec-keygen(1M), host(1M), named(1M), nslookup(1M), attributes(5)
RFC 1035
See the BIND 9 Administrator's Reference Manual. As of the date of pub‐
lication 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 11 Jan 2010 dig(1M)