MDIG(1) BIND 9 MDIG(1)
NAME
mdig - DNS pipelined lookup utility
SYNOPSIS
mdig ]8;;mailto:{@server\{@server]8;;\} [-f filename] [-h] [-v] [ [-4] | [-6] ] [-m] [-b address]
[-p port#] [-c class] [-t type] [-i] [-x addr] [plusopt...]
mdig {-h}
mdig [@server] {global-opt...} { {local-opt...} {query} ...}
DESCRIPTION
mdig is a multiple/pipelined query version of dig: instead of waiting
for a response after sending each query, it begins by sending all
queries. Responses are displayed in the order in which they are re-
ceived, not in the order the corresponding queries were sent.
mdig options are a subset of the dig options, and are divided into "any-
where options," which can occur anywhere, "global options," which must
occur before the query name (or they are ignored with a warning), and
"local options," which apply to the next query on the command line.
The @server option is a mandatory global option. It is the name or IP
address of the name server to query. (Unlike dig, this value is not re-
trieved from /etc/resolv.conf.) It can be an IPv4 address in dotted-dec-
imal notation, an IPv6 address in colon-delimited notation, or a host-
name. When the supplied server argument is a hostname, mdig resolves
that name before querying the name server.
mdig 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 an-
swer 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.
ANYWHERE OPTIONS
-f This option makes mdig operate in batch mode by reading a list of
lookup requests to process from the file filename. The file con-
tains 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 mdig using the command-line interface.
-h This option causes mdig to print detailed help information, with
the full list of options, and exit.
-v This option causes mdig to print the version number and exit.
GLOBAL OPTIONS
-4 This option forces mdig to only use IPv4 query transport.
-6 This option forces mdig to only use IPv6 query transport.
-b address
This option sets the source IP address of the query to address.
This must be a valid address on one of the host's network inter-
faces or "0.0.0.0" or "::". An optional port may be specified by
appending "#<port>"
-m This option enables memory usage debugging.
-p port#
This option is used when a non-standard port number is to be
queried. port# is the port number that mdig sends its queries to,
instead of the standard DNS port number 53. This option is used
to test a name server that has been configured to listen for
queries on a non-standard port number.
The global query options are:
+additional, +noadditional
This option displays [or does not display] the additional section
of a reply. The default is to display it.
+all, +noall
This option sets or clears all display flags.
+answer, +noanswer
This option displays [or does not display] the answer section of
a reply. The default is to display it.
+authority, +noauthority
This option displays [or does not display] the authority section
of a reply. The default is to display it.
+besteffort, +nobesteffort
This option attempts to display [or does not display] the con-
tents of messages which are malformed. The default is to not dis-
play malformed answers.
+burst This option delays queries until the start of the next second.
+cl, +nocl
This option displays [or does not display] the CLASS when print-
ing the record.
+comments, +nocomments
This option toggles the display of comment lines in the output.
The default is to print comments.
+continue, +nocontinue
This option toggles continuation on errors (e.g. timeouts).
+crypto, +nocrypto
This option toggles the display of cryptographic fields in DNSSEC
records. The contents of these fields 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]"; in the
DNSKEY case, the key ID is displayed as the replacement, e.g., [
key id = value ].
+multiline, +nomultiline
This option toggles printing of records, like the SOA records, in
a verbose multi-line format with human-readable comments. The de-
fault is to print each record on a single line, to facilitate ma-
chine parsing of the mdig output.
+question, +noquestion
This option prints [or does not print] the question section of a
query when an answer is returned. The default is to print the
question section as a comment.
+rrcomments, +norrcomments
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 mul-
tiline mode is active.
+short, +noshort
This option provides [or does not provide] a terse answer. The
default is to print the answer in a verbose form.
+split=W
This option splits long hex- or base64-formatted fields in re-
source 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. The default is 56 characters, or 44 characters
when multiline mode is active.
+tcp, +notcp
This option uses [or does not use] TCP when querying name
servers. The default behavior is to use UDP.
+ttlid, +nottlid
This option displays [or does not display] the TTL when printing
the record.
+ttlunits, +nottlunits
This option displays [or does not display] the TTL in friendly
human-readable time units of "s", "m", "h", "d", and "w", repre-
senting seconds, minutes, hours, days, and weeks. This implies
+ttlid.
+vc, +novc
This option uses [or does not use] TCP when querying name
servers. This alternate syntax to +tcp is provided for backwards
compatibility. The vc stands for "virtual circuit".
LOCAL OPTIONS
-c class
This option sets the query class to class. It can be any valid
query class which is supported in BIND 9. The default query class
is "IN".
-t type
This option sets the query type to type. It can be any valid
query type which is supported in BIND 9. The default query type
is "A", unless the -x option is supplied to indicate a reverse
lookup with the "PTR" query type.
-x addr
Reverse lookups - mapping addresses to names - are simplified by
this option. addr is an IPv4 address in dotted-decimal notation,
or a colon-delimited IPv6 address. mdig automatically performs a
lookup for a query 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.
The local query options are:
+aaflag, +noaaflag
This is a synonym for +aaonly, +noaaonly.
+aaonly, +noaaonly
This sets the aa flag in the query.
+adflag, +noadflag
This sets [or does not set] the AD (authentic data) bit in the
query. This requests the server to return whether all of the an-
swer 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 indicates that some part of the
answer was insecure or not validated. This bit is set by de-
fault.
+bufsize=B
This 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. Values outside this range are rounded up or down
appropriately. Values other than zero cause a EDNS query to be
sent.
+cdflag, +nocdflag
This sets [or does not set] the CD (checking disabled) bit in the
query. This requests the server to not perform DNSSEC validation
of responses.
+cookie=####, +nocookie
This sends [or does not send] a COOKIE EDNS option, with an op-
tional value. Replaying a COOKIE from a previous response allows
the server to identify a previous client. The default is +no-
cookie.
+dnssec, +nodnssec
This requests that DNSSEC records be sent by setting the DNSSEC
OK (DO) bit in the OPT record in the additional section of the
query.
+edns[=#], +noedns
This specifies [or does not specify] the EDNS version to query
with. Valid values are 0 to 255. Setting the EDNS version causes
an EDNS query to be sent. +noedns clears the remembered EDNS
version. EDNS is set to 0 by default.
+ednsflags[=#], +noednsflags
This sets the must-be-zero EDNS flag bits (Z bits) to the speci-
fied value. Decimal, hex, and octal encodings are accepted. Set-
ting a named flag (e.g. DO) is silently ignored. By default, no Z
bits are set.
+ednsopt[=code[:value]], +noednsopt
This specifies [or does not specify] an EDNS option with code
point code and an optional payload of value as a hexadecimal
string. +noednsopt clears the EDNS options to be sent.
+expire, +noexpire
This toggles sending of an EDNS Expire option.
+nsid, +nonsid
This toggles inclusion of an EDNS name server ID request when
sending a query.
+recurse, +norecurse
This toggles the setting of the RD (recursion desired) bit in the
query. This bit is set by default, which means mdig normally
sends recursive queries.
+retry=T
This 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.
+subnet=addr[/prefix-length], +nosubnet
This sends [or does not send] an EDNS Client Subnet option with
the specified IP address or network prefix.
mdig +subnet=0.0.0.0/0, or simply mdig +subnet=0
This 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.
+timeout=T
This sets the timeout for a query to T seconds. The default time-
out is 5 seconds for UDP transport and 10 for TCP. An attempt to
set T to less than 1 results in a query timeout of 1 second being
applied.
+tries=T
This 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.
+udptimeout=T
This sets the timeout between UDP query retries to T.
+unknownformat, +nounknownformat
This prints [or does not print] all RDATA in unknown RR-type pre-
sentation format (see ]8;;https://datatracker.ietf.org/doc/html/rfc3597.html\RFC 3597]8;;\). The default is to print RDATA
for known types in the type's presentation format.
+yaml, +noyaml
This toggles printing of the responses in a detailed YAML format.
+zflag, +nozflag
This sets [or does not set] the last unassigned DNS header flag
in a DNS query. This flag is off by default.
SEE ALSO
dig(1), ]8;;https://datatracker.ietf.org/doc/html/rfc1035.html\RFC 1035]8;;\.
AUTHOR
Internet Systems Consortium
COPYRIGHT
2025, Internet Systems Consortium
9.20.15-1~deb13u1-Debian 2025-10-18 MDIG(1)
Generated by dwww version 1.16 on Tue Dec 16 06:23:56 CET 2025.