OPTIONS¶
-4
Use IPv4 only.
-6
Use IPv6 only.
-b address[#port]
Set the source IP address of the query. The
address 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
Set the query class. The default class is IN;
other classes are HS for Hesiod records or CH for Chaosnet records.
-f file
Batch mode: dig reads a list of lookup requests to
process from the given file. Each line in the file should be organized
in the same way they would be presented as queries to dig using the
command-line interface.
-i
Do reverse IPv6 lookups using the obsolete RFC 1886
IP6.INT domain, which is no longer in use. Obsolete bit string label queries
(RFC 2874) are not attempted.
-k keyfile
Sign queries using TSIG using a key read from the given
file. Key files can be generated using
tsig-keygen(8). 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.
-m
Enable memory usage debugging.
-p port
Send the query to a non-standard port on the server,
instead of the default port 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.
-q name
The domain name to query. This is useful to distinguish
the name from other arguments.
-r
Do not read options from ${HOME}/.digrc. This is useful
for scripts that need predictable behaviour.
-t type
The resource record type to query. It can be any valid
query type. If it is a resource record type supported in BIND 9, it can be
given by the type mnemonic (such as "NS" or "AAAA"). The
default query type is "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, set the
type 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.
All resource record types can be expressed as "TYPEnn",
where "nn" is the number of the type. If the resource record type
is not supported in BIND 9, the result will be displayed as described in RFC
3597.
-u
Print query times in microseconds instead of
milliseconds.
-v
Print the version number and exit.
-x addr
Simplified reverse lookups, for mapping addresses to
names. The addr is an IPv4 address in dotted-decimal notation, or a
colon-delimited IPv6 address. When the -x is used, there is no need to
provide the name, class and type arguments. dig
automatically performs a lookup for a name like 94.2.0.192.in-addr.arpa and
sets the query type and class to PTR and IN respectively. IPv6 addresses are
looked up using nibble format under the IP6.ARPA domain (but see also the
-i option).
-y [hmac:]keyname:secret
Sign queries using TSIG with the given authentication
key.
keyname is the name of the key, and
secret is the base64
encoded shared secret.
hmac is the name of the key algorithm; valid
choices are hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, or
hmac-sha512. If
hmac is not specified, the default is hmac-md5 or if
MD5 was disabled hmac-sha256.
NOTE: You should use the -k option and avoid the -y
option, because with -y the shared secret is supplied as a command
line argument in clear text. This may be visible in the output from
ps(1) or in a history file maintained by the user's shell.
QUERY OPTIONS¶
dig 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
+keyword=value. Keywords may be abbreviated, provided the
abbreviation is unambiguous; for example, +cd is equivalent to +cdflag. The
query options are:
+[no]aaflag
A synonym for +[no]aaonly.
+[no]aaonly
Sets the "aa" flag in the query.
+[no]additional
Display [do not display] the additional section of a
reply. The default is to display it.
+[no]adflag
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.
+[no]all
Set or clear all display flags.
+[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]badcookie
Retry lookup with the new server cookie if a BADCOOKIE
response is received.
+[no]besteffort
Attempt to display the contents of messages which are
malformed. The default is to not display malformed answers.
+bufsize=B
This option sets the UDP message buffer size advertised
using EDNS0 to B bytes. The maximum and minimum sizes of this buffer
are 65535 and 0, respectively. +bufsize=0 disables EDNS (use +bufsize=0 +edns
to send a EDNS messages with a advertised size of 0 bytes). +bufsize restores
the default buffer size.
+[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]class
Display [do not display] the CLASS when printing the
record.
+[no]cmd
Toggles the printing of the initial comment in the
output, identifying the version of dig and the query options that have
been applied. This option always has global effect; it cannot be set globally
and then overridden on a per-lookup basis. The default is to print this
comment.
+[no]comments
Toggles the display of some comment lines in the output,
containing information about the packet header and OPT pseudosection, and the
names of the response section. The default is to print these comments.
Other types of comments in the output are not affected by this
option, but can be controlled using other command line switches. These
include +[no]cmd, +[no]question, +[no]stats, and
+[no]rrcomments.
+[no]cookie[=####]
Send a COOKIE EDNS option, with optional value. Replaying
a COOKIE from a previous response will allow the server to identify a previous
client. The default is
+cookie.
+cookie is also set when +trace is set to better emulate
the default queries from a nameserver.
+[no]crypto
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 ]".
+[no]defname
Deprecated, treated as a synonym for
+[no]search
+[no]dnssec
Requests DNSSEC records be sent by setting the DNSSEC OK
bit (DO) in the OPT record in the additional section of the query.
+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.
+dscp=value
Set the DSCP code point to be used when sending the
query. Valid DSCP code points are in the range [0..63]. By default no code
point is explicitly set.
+[no]edns[=#]
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.
+noedns clears the remembered EDNS version. EDNS is set to 0 by
default.
+[no]ednsflags[=#]
Set the must-be-zero EDNS flags bits (Z bits) to the
specified value. Decimal, hex and octal encodings are accepted. Setting a
named flag (e.g. DO) will silently be ignored. By default, no Z bits are
set.
+[no]ednsnegotiation
Enable / disable EDNS version negotiation. By default
EDNS version negotiation is enabled.
+[no]ednsopt[=code[:value]]
Specify EDNS option with code point code and
optionally payload of value as a hexadecimal string. code can be
either an EDNS option name (for example, NSID or ECS), or an arbitrary numeric
value. +noednsopt clears the EDNS options to be sent.
+[no]expire
Send an EDNS Expire option.
+[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]header-only
Send a query with a DNS header without a question
section. The default is to add a question section. The query type and query
name are ignored when this is set.
+[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]idnin
Process [do not process] IDN domain names on input. This
requires IDN SUPPORT to have been enabled at compile time.
The default is to process IDN input when standard output is a tty.
The IDN processing on input is disabled when dig output is redirected to
files, pipes, and other non-tty file descriptors.
+[no]idnout
Convert [do not convert] puny code on output. This
requires IDN SUPPORT to have been enabled at compile time.
The default is to process puny code on output when standard output
is a tty. The puny code processing on output is disabled when dig output is
redirected to files, pipes, and other non-tty file descriptors.
+[no]ignore
Ignore truncation in UDP responses instead of retrying
with TCP. By default, TCP retries are performed.
+[no]keepopen
Keep the TCP socket open between queries and reuse it
rather than creating a new TCP socket for each lookup. The default is
+nokeepopen.
+[no]mapped
Allow mapped IPv4 over IPv6 addresses to be used. The
default is +mapped.
+[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.
+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 if +search is set.
+[no]nsid
Include an EDNS name server ID request when sending a
query.
+[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]onesoa
Print only one (starting) SOA record when performing an
AXFR. The default is to print both the starting and ending SOA records.
+[no]opcode=value
Set [restore] the DNS message opcode to the specified
value. The default value is QUERY (0).
+[no]qr
Toggles the display of the query message as it is sent.
By default, the query is not printed.
+[no]question
Toggles the display of the question section of a query
when an answer is returned. The default is to print the question section as a
comment.
+[no]rdflag
A synonym for +[no]recurse.
+[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
recursive queries. Recursion is automatically disabled when using the
+nssearch option, and when using +trace except for an initial
recursive query to get the list of root servers.
+retry=T
Sets the number of times to retry UDP queries to server
to T instead of the default, 2. Unlike +tries, this does not
include the initial query.
+[no]rrcomments
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.
+[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.
'ndots' from resolv.conf (default 1) which may be overridden by
+ndots determines if the name will be treated as relative or not and
hence whether a search is eventually performed or not.
+[no]short
Provide a terse answer. The default is to print the
answer in a verbose form. This option always has global effect; it cannot be
set globally and then overridden on a per-lookup basis.
+[no]showsearch
Perform [do not perform] a search showing intermediate
results.
+[no]sigchase
Chase DNSSEC signature chains. Requires dig be compiled
with -DDIG_SIGCHASE. This feature is deprecated. Use delv
instead.
+split=W
Split long hex- or base64-formatted fields in resource
records into chunks of W characters (where W is rounded up to
the nearest multiple of 4). +nosplit or +split=0 causes fields
not to be split at all. The default is 56 characters, or 44 characters when
multiline mode is active.
+[no]stats
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 as a comment after each lookup.
+[no]subnet=addr[/prefix-length]
Send (don't send) an EDNS Client Subnet option with the
specified IP address or network prefix.
dig +subnet=0.0.0.0/0, or simply dig +subnet=0 for
short, sends an EDNS CLIENT-SUBNET option with an empty address and a source
prefix-length of zero, which signals a resolver that the client's address
information must not be used when resolving this query.
+[no]tcp
Use [do not use] TCP when querying name servers. The
default behavior is to use UDP unless a type any or ixfr=N query is requested,
in which case the default is TCP. AXFR queries always use TCP.
+timeout=T
Sets the timeout for a query to T seconds. The
default timeout is 5 seconds. An attempt to set T to less than 1 will
result in a query timeout of 1 second being applied.
+[no]topdown
When chasing DNSSEC signature chains perform a top-down
validation. Requires dig be compiled with -DDIG_SIGCHASE. This feature is
deprecated. Use delv instead.
+[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.
If @server is also specified, it affects only the initial query
for the root zone name servers.
+dnssec is also set when +trace is set to better emulate
the default queries from a nameserver.
+tries=T
Sets the number of times to try UDP queries to server to
T instead of the default, 3. If T is less than or equal to zero,
the number of tries is silently rounded up to 1.
+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. This feature is
deprecated. Use delv instead.
+[no]ttlid
Display [do not display] the TTL when printing the
record.
+[no]ttlunits
Display [do not display] the TTL in friendly
human-readable time units of "s", "m", "h",
"d", and "w", representing seconds, minutes, hours, days
and weeks. Implies +ttlid.
+[no]unknownformat
Print all RDATA in unknown RR type presentation format
(RFC 3597). The default is to print RDATA for known types in the type's
presentation format.
+[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]zflag
Set [do not set] the last unassigned DNS header flag in a
DNS query. This flag is off by default.