bind/doc/man/dig.1in

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.TH "DIG" "1" "@RELEASE_DATE@" "@PACKAGE_VERSION@" "BIND 9"
.SH NAME
dig \- DNS lookup utility
.SH SYNOPSIS
.sp
\fBdig\fP [@server] [\fB\-b\fP address] [\fB\-c\fP class] [\fB\-f\fP filename] [\fB\-k\fP filename] [\fB\-m\fP] [\fB\-p\fP port#] [\fB\-q\fP name] [\fB\-t\fP type] [\fB\-v\fP] [\fB\-x\fP addr] [\fB\-y\fP [hmac:]name:key] [ [\fB\-4\fP] | [\fB\-6\fP] ] [name] [type] [class] [queryopt...]
.sp
\fBdig\fP [\fB\-h\fP]
.sp
\fBdig\fP [global\-queryopt...] [query...]
.SH DESCRIPTION
.sp
\fBdig\fP 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 \fBdig\fP to
troubleshoot DNS problems because of its flexibility, ease of use, and
clarity of output. Other lookup tools tend to have less functionality
than \fBdig\fP\&.
.sp
Although \fBdig\fP 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 \fI\%\-h\fP option is given. The BIND 9
implementation of \fBdig\fP allows multiple lookups to be issued from the
command line.
.sp
Unless it is told to query a specific name server, \fBdig\fP tries each
of the servers listed in \fB/etc/resolv.conf\fP\&. If no usable server
addresses are found, \fBdig\fP sends the query to the local host.
.sp
When no command\-line arguments or options are given, \fBdig\fP
performs an NS query for "." (the root).
.sp
It is possible to set per\-user defaults for \fBdig\fP via
\fB${HOME}/.digrc\fP\&. This file is read and any options in it are applied
before the command\-line arguments. The \fI\%\-r\fP option disables this
feature, for scripts that need predictable behavior.
.sp
The IN and CH class names overlap with the IN and CH top\-level domain
names. Either use the \fI\%\-t\fP and \fI\%\-c\fP options to specify the type and
class, use the \fI\%\-q\fP to specify the domain name, or use "IN." and
"CH." when looking up these top\-level domains.
.SH SIMPLE USAGE
.sp
A typical invocation of \fBdig\fP looks like:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
dig @server name type
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
where:
.INDENT 0.0
.TP
.B server
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 \fBserver\fP argument is a
hostname, \fBdig\fP resolves that name before querying that name
server.
.sp
If no \fBserver\fP argument is provided, \fBdig\fP consults
\fB/etc/resolv.conf\fP; if an address is found there, it queries the
name server at that address. If either of the \fI\%\-4\fP or \fI\%\-6\fP
options are in use, then only addresses for the corresponding
transport are tried. If no usable addresses are found, \fBdig\fP
sends the query to the local host. The reply from the name server
that responds is displayed.
.UNINDENT
.INDENT 0.0
.TP
.B name
is the name of the resource record that is to be looked up.
.UNINDENT
.INDENT 0.0
.TP
.B type
indicates what type of query is required \- ANY, A, MX, SIG, etc.
\fBtype\fP can be any valid query type. If no \fBtype\fP argument is
supplied, \fBdig\fP performs a lookup for an A record.
.UNINDENT
.SH OPTIONS
.INDENT 0.0
.TP
.B \-4
This option indicates that only IPv4 should be used.
.UNINDENT
.INDENT 0.0
.TP
.B \-6
This option indicates that only IPv6 should be used.
.UNINDENT
.INDENT 0.0
.TP
.B \-b address[#port]
This option sets the source IP address of the query. The \fBaddress\fP must be a
valid address on one of the host\(aqs network interfaces, or "0.0.0.0"
or "::". An optional port may be specified by appending \fB#port\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B \-c class
This option sets the query class. The default \fBclass\fP is IN; other classes are
HS for Hesiod records or CH for Chaosnet records.
.UNINDENT
.INDENT 0.0
.TP
.B \-f file
This option sets batch mode, in which \fBdig\fP reads a list of lookup requests to process from
the given \fBfile\fP\&. Each line in the file should be organized in the
same way it would be presented as a query to \fBdig\fP using the
command\-line interface.
.UNINDENT
.INDENT 0.0
.TP
.B \-h
Print a usage summary.
.UNINDENT
.INDENT 0.0
.TP
.B \-k keyfile
This option tells \fBnamed\fP to sign queries using TSIG using a key read from the given file. Key
files can be generated using \fBtsig\-keygen\fP\&. When using TSIG
authentication with \fBdig\fP, 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 \fBkey\fP and \fBserver\fP statements in
\fBnamed.conf\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B \-m
This option enables memory usage debugging.
.UNINDENT
.INDENT 0.0
.TP
.B \-p port
This option sends the query to a non\-standard port on the server, instead of the
default port 53. This option is used to test a name server that
has been configured to listen for queries on a non\-standard port
number.
.UNINDENT
.INDENT 0.0
.TP
.B \-q name
This option specifies the domain name to query. This is useful to distinguish the \fBname\fP
from other arguments.
.UNINDENT
.INDENT 0.0
.TP
.B \-r
This option indicates that options from \fB${HOME}/.digrc\fP should not be read. This is useful for
scripts that need predictable behavior.
.UNINDENT
.INDENT 0.0
.TP
.B \-t type
This option indicates the resource record type to query, which 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 \fBNS\fP or \fBAAAA\fP). The default query type is
\fBA\fP, unless the \fI\%\-x\fP 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
\fBtype\fP to \fBixfr=N\fP\&. The incremental zone transfer contains
all changes made to the zone since the serial number in the zone\(aqs
SOA record was \fBN\fP\&.
.sp
All resource record types can be expressed as \fBTYPEnn\fP, where \fBnn\fP is
the number of the type. If the resource record type is not supported
in BIND 9, the result is displayed as described in \fI\%RFC 3597\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B \-u
This option indicates that print query times should be provided in microseconds instead of milliseconds.
.UNINDENT
.INDENT 0.0
.TP
.B \-v
This option prints the version number and exits.
.UNINDENT
.INDENT 0.0
.TP
.B \-x addr
This option sets simplified reverse lookups, for mapping addresses to names. The
\fBaddr\fP is an IPv4 address in dotted\-decimal notation, or a
colon\-delimited IPv6 address. When the \fI\%\-x\fP option is used, there is no
need to provide the \fBname\fP, \fBclass\fP, and \fBtype\fP arguments.
\fBdig\fP automatically performs a lookup for a name like
\fB94.2.0.192.in\-addr.arpa\fP 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.
.UNINDENT
.INDENT 0.0
.TP
.B \-y [hmac:]keyname:secret
This option signs queries using TSIG with the given authentication key.
\fBkeyname\fP is the name of the key, and \fBsecret\fP is the
base64\-encoded shared secret. \fBhmac\fP is the name of the key algorithm;
valid choices are \fBhmac\-md5\fP, \fBhmac\-sha1\fP, \fBhmac\-sha224\fP,
\fBhmac\-sha256\fP, \fBhmac\-sha384\fP, or \fBhmac\-sha512\fP\&. If \fBhmac\fP is
not specified, the default is \fBhmac\-md5\fP; if MD5 was disabled, the default is
\fBhmac\-sha256\fP\&.
.UNINDENT
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Only the \fI\%\-k\fP option should be used, rather than the \fI\%\-y\fP option,
because with \fI\%\-y\fP the shared secret is supplied as a command\-line
argument in clear text. This may be visible in the output from \fBps1\fP or
in a history file maintained by the user\(aqs shell.
.UNINDENT
.UNINDENT
.SH QUERY OPTIONS
.sp
\fBdig\fP 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.
.sp
Each query option is identified by a keyword preceded by a plus sign
(\fB+\fP). Some keywords set or reset an option; these may be preceded by
the string \fBno\fP to negate the meaning of that keyword. Other keywords
assign values to options, like the timeout interval. They have the form
\fB+keyword=value\fP\&. Keywords may be abbreviated, provided the
abbreviation is unambiguous; for example, \fB+cd\fP is equivalent to
\fB+cdflag\fP\&. The query options are:
.INDENT 0.0
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.B +[no]aaflag
This option is a synonym for \fB+[no]aaonly\fP\&.
.UNINDENT
.INDENT 0.0
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.B +[no]aaonly
This option sets the \fBaa\fP flag in the query.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]additional
This option displays [or does not display] the additional section of a reply. The
default is to display it.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]adflag
This option sets [or does 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 been validated as secure, according to the security
policy of the server. \fBAD=1\fP indicates that all records have been
validated as secure and the answer is not from a OPT\-OUT range. \fBAD=0\fP
indicates that some part of the answer was insecure or not validated.
This bit is set by default.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]all
This option sets or clears all display flags.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]answer
This option displays [or does not display] the answer section of a reply. The default
is to display it.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]authority
This option displays [or does not display] the authority section of a reply. The
default is to display it.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]badcookie
This option retries the lookup with a new server cookie if a BADCOOKIE response is
received.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]besteffort
This option attempts to display the contents of messages which are malformed. The
default is to not display malformed answers.
.UNINDENT
.INDENT 0.0
.TP
.B +bufsize[=B]
This option sets the UDP message buffer size advertised using EDNS0 to
\fBB\fP bytes.  The maximum and minimum sizes of this buffer are 65535 and
0, respectively.  \fB+bufsize\fP restores the default buffer size.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]cdflag
This option sets [or does not set] the CD (checking disabled) bit in the query. This
requests the server to not perform DNSSEC validation of responses.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]class
This option displays [or does not display] the CLASS when printing the record.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]cmd
This option toggles the printing of the initial comment in the output, identifying the
version of \fBdig\fP and the query options that have been applied. This option
always has a global effect; it cannot be set globally and then overridden on a
per\-lookup basis. The default is to print this comment.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]comments
This option toggles the display of some comment lines in the output, with
information about the packet header and OPT pseudosection, and the names of
the response section. The default is to print these comments.
.sp
Other types of comments in the output are not affected by this option, but
can be controlled using other command\-line switches. These include
\fB+[no]cmd\fP, \fB+[no]question\fP, \fB+[no]stats\fP, and \fB+[no]rrcomments\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]cookie=####
This option sends [or does not send] a COOKIE EDNS option, with an optional value. Replaying a COOKIE
from a previous response allows the server to identify a previous
client. The default is \fB+cookie\fP\&.
.sp
\fB+cookie\fP is also set when \fB+trace\fP is set to better emulate the
default queries from a nameserver.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]crypto
This option toggles the display of cryptographic fields in DNSSEC records. The
contents of these fields are unnecessary for debugging 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 \fB[omitted]\fP or, in the DNSKEY case, the
key ID is displayed as the replacement, e.g. \fB[ key id = value ]\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]defname
This option, which is deprecated, is treated as a synonym for \fB+[no]search\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]dns64prefix
Lookup IPV4ONLY.ARPA AAAA and print any DNS64 prefixes found.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]dnssec
This option requests that DNSSEC records be sent by setting the DNSSEC OK (DO) bit in
the OPT record in the additional section of the query.
.UNINDENT
.INDENT 0.0
.TP
.B +domain=somename
This option sets the search list to contain the single domain \fBsomename\fP, as if
specified in a \fBdomain\fP directive in \fB/etc/resolv.conf\fP, and
enables search list processing as if the \fB+search\fP option were
given.
.UNINDENT
.INDENT 0.0
.TP
.B +dscp=value
This option sets 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.
.UNINDENT
.INDENT 0.0
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.B +[no]edns[=#]
This option specifies the EDNS version to query with. Valid values are 0 to 255.
Setting the EDNS version causes an EDNS query to be sent.
\fB+noedns\fP clears the remembered EDNS version. EDNS is set to 0 by
default.
.UNINDENT
.INDENT 0.0
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.B +[no]ednsflags[=#]
This option sets 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) is silently ignored. By default, no Z bits are set.
.UNINDENT
.INDENT 0.0
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.B +[no]ednsnegotiation
This option enables/disables EDNS version negotiation. By default, EDNS version
negotiation is enabled.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]ednsopt[=code[:value]]
This option specifies the EDNS option with code point \fBcode\fP and an optional payload
of \fBvalue\fP as a hexadecimal string. \fBcode\fP can be either an EDNS
option name (for example, \fBNSID\fP or \fBECS\fP) or an arbitrary
numeric value. \fB+noednsopt\fP clears the EDNS options to be sent.
.UNINDENT
.INDENT 0.0
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.B +[no]expire
This option sends an EDNS Expire option.
.UNINDENT
.INDENT 0.0
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.B +[no]fail
This option indicates that \fBnamed\fP should try [or not try] the next server if a SERVFAIL is received. The default is
to not try the next server, which is the reverse of normal stub
resolver behavior.
.UNINDENT
.INDENT 0.0
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.B +[no]header\-only
This option sends 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.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]https[=value]
This option indicates whether to use DNS over HTTPS (DoH) when querying
name servers.  When this option is in use, the port number defaults to 443.
The HTTP POST request mode is used when sending the query.
.sp
If \fBvalue\fP is specified, it will be used as the HTTP endpoint in the
query URI; the default is \fB/dns\-query\fP\&. So, for example, \fBdig
@example.com +https\fP will use the URI \fBhttps://example.com/dns\-query\fP\&.
.UNINDENT
.INDENT 0.0
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.B +[no]https\-get[=value]
Similar to \fB+https\fP, except that the HTTP GET request mode is used
when sending the query.
.UNINDENT
.INDENT 0.0
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.B +[no]https\-post[=value]
Same as \fB+https\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]http\-plain[=value]
Similar to \fB+https\fP, except that HTTP queries will be sent over a
non\-encrypted channel. When this option is in use, the port number
defaults to 80 and the HTTP request mode is POST.
.UNINDENT
.INDENT 0.0
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.B +[no]http\-plain\-get[=value]
Similar to \fB+http\-plain\fP, except that the HTTP request mode is GET.
.UNINDENT
.INDENT 0.0
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.B +[no]http\-plain\-post[=value]
Same as \fB+http\-plain\fP\&.
.UNINDENT
.INDENT 0.0
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.B +[no]identify
This option shows [or does not show] the IP address and port number that
supplied the answer, when the \fB+short\fP 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.
.UNINDENT
.INDENT 0.0
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.B +[no]idnin
This option processes [or does not process] IDN domain names on input. This requires
\fBIDN SUPPORT\fP to have been enabled at compile time.
.sp
The default is to process IDN input when standard output is a tty.
The IDN processing on input is disabled when \fBdig\fP output is redirected
to files, pipes, and other non\-tty file descriptors.
.UNINDENT
.INDENT 0.0
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.B +[no]idnout
This option converts [or does not convert] puny code on output. This requires
\fBIDN SUPPORT\fP to have been enabled at compile time.
.sp
The default is to process puny code on output when standard output is
a tty. The puny code processing on output is disabled when \fBdig\fP output
is redirected to files, pipes, and other non\-tty file descriptors.
.UNINDENT
.INDENT 0.0
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.B +[no]ignore
This option ignores [or does not ignore] truncation in UDP responses instead of retrying with TCP. By
default, TCP retries are performed.
.UNINDENT
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.B +[no]keepalive
This option sends [or does not send] an EDNS Keepalive option.
.UNINDENT
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.B +[no]keepopen
This option keeps [or does not keep] the TCP socket open between queries, and reuses it rather than
creating a new TCP socket for each lookup. The default is
\fB+nokeepopen\fP\&.
.UNINDENT
.INDENT 0.0
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.B +[no]multiline
This option prints [or does not 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 \fBdig\fP output.
.UNINDENT
.INDENT 0.0
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.B +ndots=D
This option sets the number of dots (\fBD\fP) that must appear in \fBname\fP for
it to be considered absolute. The default value is that defined using
the \fBndots\fP statement in \fB/etc/resolv.conf\fP, or 1 if no \fBndots\fP
statement is present. Names with fewer dots are interpreted as
relative names, and are searched for in the domains listed in the
\fBsearch\fP or \fBdomain\fP directive in \fB/etc/resolv.conf\fP if
\fB+search\fP is set.
.UNINDENT
.INDENT 0.0
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.B +[no]nsid
When enabled, this option includes an EDNS name server ID request when sending a query.
.UNINDENT
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.B +[no]nssearch
When this option is set, \fBdig\fP 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.
Addresses of servers that did not respond are also printed.
.UNINDENT
.INDENT 0.0
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.B +[no]onesoa
When enabled, this option prints only one (starting) SOA record when performing an AXFR. The
default is to print both the starting and ending SOA records.
.UNINDENT
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.B +[no]opcode=value
When enabled, this option sets (restores) the DNS message opcode to the specified value. The
default value is QUERY (0).
.UNINDENT
.INDENT 0.0
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.B +padding=value
This option pads the size of the query packet using the EDNS Padding option to
blocks of \fBvalue\fP bytes. For example, \fB+padding=32\fP causes a
48\-byte query to be padded to 64 bytes. The default block size is 0,
which disables padding; the maximum is 512. Values are ordinarily
expected to be powers of two, such as 128; however, this is not
mandatory. Responses to padded queries may also be padded, but only
if the query uses TCP or DNS COOKIE.
.UNINDENT
.INDENT 0.0
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.B +qid=value
This option specifies the query ID to use when sending queries.
.UNINDENT
.INDENT 0.0
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.B +[no]qr
This option toggles the display of the query message as it is sent. By default, the query
is not printed.
.UNINDENT
.INDENT 0.0
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.B +[no]question
This option 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.
.UNINDENT
.INDENT 0.0
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.B +[no]raflag
This option sets [or does not set] the RA (Recursion Available) bit in the query. The
default is \fB+noraflag\fP\&. This bit is ignored by the server for
QUERY.
.UNINDENT
.INDENT 0.0
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.B +[no]rdflag
This option is a synonym for \fB+[no]recurse\fP\&.
.UNINDENT
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.B +[no]recurse
This option toggles the setting of the RD (recursion desired) bit in the query.
This bit is set by default, which means \fBdig\fP normally sends
recursive queries. Recursion is automatically disabled when the
\fB+nssearch\fP or \fB+trace\fP query option is used.
.UNINDENT
.INDENT 0.0
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.B +retry=T
This option sets the number of times to retry UDP and TCP queries to server to \fBT\fP
instead of the default, 2.  Unlike \fB+tries\fP, this does not include
the initial query.
.UNINDENT
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.B +[no]rrcomments
This option toggles 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.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]search
This option uses [or does not use] the search list defined by the searchlist or domain
directive in \fBresolv.conf\fP, if any. The search list is not used by
default.
.sp
\fBndots\fP from \fBresolv.conf\fP (default 1), which may be overridden by
\fB+ndots\fP, determines whether the name is treated as relative
and hence whether a search is eventually performed.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]short
This option toggles whether a terse answer is provided. The default is to print the answer in a verbose
form. This option always has a global effect; it cannot be set globally and
then overridden on a per\-lookup basis.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]showbadcookie
This option toggles whether to show the message containing the
BADCOOKIE rcode before retrying the request or not. The default
is to not show the messages.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]showsearch
This option performs [or does not perform] a search showing intermediate results.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]sigchase
This feature is now obsolete and has been removed; use \fBdelv\fP
instead.
.UNINDENT
.INDENT 0.0
.TP
.B +split=W
This option splits long hex\- or base64\-formatted fields in resource records into
chunks of \fBW\fP characters (where \fBW\fP is rounded up to the nearest
multiple of 4). \fB+nosplit\fP or \fB+split=0\fP causes fields not to be
split at all. The default is 56 characters, or 44 characters when
multiline mode is active.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]stats
This option toggles the printing of statistics: when the query was made, the size of the
reply, etc. The default behavior is to print the query statistics as a
comment after each lookup.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]subnet=addr[/prefix\-length]
This option sends [or does not send] an EDNS CLIENT\-SUBNET option with the specified IP
address or network prefix.
.sp
\fBdig +subnet=0.0.0.0/0\fP, or simply \fBdig +subnet=0\fP 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\(aqs
address information must \fInot\fP be used when resolving this query.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]tcflag
This option sets [or does not set] the TC (TrunCation) bit in the query. The default is
\fB+notcflag\fP\&. This bit is ignored by the server for QUERY.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]tcp
This option indicates whether to use TCP when querying name servers.
The default behavior is to use UDP unless a type \fBany\fP or \fBixfr=N\fP
query is requested, in which case the default is TCP. AXFR queries
always use TCP.
.UNINDENT
.INDENT 0.0
.TP
.B +timeout=T
This option sets the timeout for a query to \fBT\fP seconds. The default timeout is
5 seconds. An attempt to set \fBT\fP to less than 1 is silently set to 1.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]tls
This option indicates whether to use DNS over TLS (DoT) when querying
name servers. When this option is in use, the port number defaults
to 853.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]topdown
This feature is related to \fBdig +sigchase\fP, which is obsolete and
has been removed. Use \fBdelv\fP instead.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]trace
This option toggles 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, \fBdig\fP makes iterative queries to resolve the
name being looked up. It follows referrals from the root servers,
showing the answer from each server that was used to resolve the
lookup.
.sp
If \fB@server\fP is also specified, it affects only the initial query for
the root zone name servers.
.sp
\fB+dnssec\fP is also set when \fB+trace\fP is set, to better emulate the
default queries from a name server.
.UNINDENT
.INDENT 0.0
.TP
.B +tries=T
This option sets the number of times to try UDP and TCP queries to server to \fBT\fP
instead of the default, 3. If \fBT\fP is less than or equal to zero,
the number of tries is silently rounded up to 1.
.UNINDENT
.INDENT 0.0
.TP
.B +trusted\-key=####
This option formerly specified trusted keys for use with \fBdig +sigchase\fP\&. This
feature is now obsolete and has been removed; use \fBdelv\fP instead.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]ttlid
This option displays [or does not display] the TTL when printing the record.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]ttlunits
This option displays [or does not display] the TTL in friendly human\-readable time
units of \fBs\fP, \fBm\fP, \fBh\fP, \fBd\fP, and \fBw\fP, representing seconds, minutes,
hours, days, and weeks. This implies \fB+ttlid\fP\&.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]unknownformat
This option prints all RDATA in unknown RR type presentation format (\fI\%RFC 3597\fP).
The default is to print RDATA for known types in the type\(aqs
presentation format.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]vc
This option uses [or does not use] TCP when querying name servers. This alternate
syntax to \fB+[no]tcp\fP is provided for backwards compatibility. The
\fBvc\fP stands for "virtual circuit."
.UNINDENT
.INDENT 0.0
.TP
.B +[no]yaml
When enabled, this option prints the responses (and, if \fB+qr\fP is in use, also the
outgoing queries) in a detailed YAML format.
.UNINDENT
.INDENT 0.0
.TP
.B +[no]zflag
This option sets [or does not set] the last unassigned DNS header flag in a DNS query.
This flag is off by default.
.UNINDENT
.SH MULTIPLE QUERIES
.sp
The BIND 9 implementation of \fBdig\fP supports specifying multiple
queries on the command line (in addition to supporting the \fI\%\-f\fP batch
file option). Each of those queries can be supplied with its own set of
flags, options, and query options.
.sp
In this case, each \fBquery\fP argument represents 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.
.sp
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 \fB+[no]cmd\fP and
\fB+[no]short\fP options) can be overridden by a query\-specific set of
query options. For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
dig +qr www.isc.org any \-x 127.0.0.1 isc.org ns +noqr
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
shows how \fBdig\fP can be used from the command line to make three
lookups: an ANY query for \fBwww.isc.org\fP, a reverse lookup of 127.0.0.1,
and a query for the NS records of \fBisc.org\fP\&. A global query option of
\fB+qr\fP is applied, so that \fBdig\fP shows the initial query it made for
each lookup. The final query has a local query option of \fB+noqr\fP which
means that \fBdig\fP does not print the initial query when it looks up the
NS records for \fBisc.org\fP\&.
.SH IDN SUPPORT
.sp
If \fBdig\fP has been built with IDN (internationalized domain name)
support, it can accept and display non\-ASCII domain names. \fBdig\fP
appropriately converts character encoding of a domain name before sending
a request to a DNS server or displaying a reply from the server.
To turn off IDN support, use the parameters
\fB+noidnin\fP and \fB+noidnout\fP, or define the \fBIDN_DISABLE\fP environment
variable.
.SH RETURN CODES
.sp
\fBdig\fP return codes are:
.INDENT 0.0
.TP
.B \fB0\fP
DNS response received, including NXDOMAIN status
.TP
.B \fB1\fP
Usage error
.TP
.B \fB8\fP
Couldn\(aqt open batch file
.TP
.B \fB9\fP
No reply from server
.TP
.B \fB10\fP
Internal error
.UNINDENT
.SH FILES
.sp
\fB/etc/resolv.conf\fP
.sp
\fB${HOME}/.digrc\fP
.SH SEE ALSO
.sp
\fBdelv(1)\fP, \fBhost(1)\fP, \fBnamed(8)\fP, \fBdnssec\-keygen(8)\fP, \fI\%RFC 1035\fP\&.
.SH BUGS
.sp
There are probably too many query options.
.SH AUTHOR
Internet Systems Consortium
.SH COPYRIGHT
2022, Internet Systems Consortium
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