dig(1)



DIG(1)                              BIND 9                              DIG(1)

NAME
       dig - DNS lookup utility

SYNOPSIS
       dig  [@server] [-b address] [-c class] [-f filename] [-k filename] [-m]
       [-p port#] [-q name] [-t type] [-v] [-x addr]  [-y  [hmac:]name:key]  [
       [-4] | [-6] ] [name] [type] [class] [queryopt...]

       dig [-h]

       dig [global-queryopt...] [query...]

DESCRIPTION
       dig  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 trou-
       bleshoot DNS problems because of its flexibility, ease of use and clar-
       ity  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 given. 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 will try each of
       the  servers  listed in /etc/resolv.conf. If no usable server addresses
       are found, dig will send the query to the local host.

       When no command line arguments or options are given, dig  will  perform
       an NS query for "." (the root).

       It  is  possible  to  set per-user defaults for dig via ${HOME}/.digrc.
       This file is read and any options in it are applied before the  command
       line  arguments.  The -r option disables this feature, for scripts that
       need predictable behaviour.

       The IN and CH class names overlap with the IN and CH top  level  domain
       names.  Either use the -t and -c options to specify the type and class,
       use the -q the specify the domain name, or use  "IN."  and  "CH."  when
       looking up these top level domains.

SIMPLE USAGE
       A typical invocation of dig looks like:

          dig @server name type

       where:

       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 server argument
              is a hostname, dig resolves that name before querying that  name
              server.

              If  no  server  argument  is  provided,  dig  consults  /etc/re-
              solv.conf; if an address is found there,  it  queries  the  name
              server at that address. If either of the -4 or -6 options are in
              use, then only addresses for the corresponding transport will be
              tried. If no usable addresses are found, dig will send the query
              to the local host. The reply from the name server that  responds
              is displayed.

       name   is the name of the resource record that is to be looked up.

       type   indicates  what type of query is required MDASH ANY, A, MX, SIG,
              etc.  type can be any valid query type. If no type  argument  is
              supplied, dig will perform a lookup for an A record.

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 append-
              ing "#<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.

       -k keyfile
              Sign queries using TSIG using a key read from  the  given  file.
              Key  files  can be generated using tsig-keygen8. 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 se-
              rial 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  de-
              scribed 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  auto-
              matically    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.

       -y [hmac:]keyname:secret
              Sign queries using TSIG with the given authentication key.  key-
              name  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  de-
              fault 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 ps1 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 an-
       swer  get  printed,  and others determine the timeout and retry strate-
       gies.

       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. Keywords may be abbreviated, provided the  abbreviation  is
       unambiguous;  for  example, +cd is equivalent to +cdflag. The query op-
       tions 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  au-
              thority  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 de-
              fault 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 re-
              sponses.

       +[no]class
              Display [do not display] the CLASS when printing the record.

       +[no]cmd
              Toggles the printing of the initial comment in the output, iden-
              tifying 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, con-
              taining information about the packet header and  OPT  pseudosec-
              tion,  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  iden-
              tify a previous client. The default is +cookie.

              +cookie is also set when +trace is set to better emulate the de-
              fault 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 ver-
              sion 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 op-
              tion 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 de-
              fault is to not try the next server which is the reverse of nor-
              mal 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 sup-
              plied 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 re-
              quires 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 out-
              put 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]keepalive
              Send [or do not send] an EDNS Keepalive option.

       +[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  for-
              mat  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 us-
              ing  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.  Addresses of servers that that did not respond  are  also
              printed.

       +[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).

       +padding=value
              Pad the size of the query packet using the EDNS  Padding  option
              to blocks of value bytes. For example, +padding=32 would cause 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 or-
              dinarily 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.

       +[no]qr
              Toggles the display of the query message as it is sent.  By  de-
              fault, 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  sec-
              tion as a comment.

       +[no]raflag
              Set  [do not set] the RA (Recursion Available) bit in the query.
              The default is +noraflag. This bit  should  be  ignored  by  the
              server for QUERY.

       +[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 the +nssearch or +trace query options are used.

       +retry=T
              Sets the number of times to retry UDP queries to server to T in-
              stead  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 ex-
              ample, 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
              This  feature is now obsolete and has been removed; use delv in-
              stead.

       +split=W
              Split long hex- or base64-formatted fields in  resource  records
              into  chunks of W characters (where W is rounded up to the near-
              est 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  speci-
              fied 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]tcflag
              Set  [do  not set] the TC (TrunCation) bit in the query. The de-
              fault is +notcflag. This bit should be ignored by the server for
              QUERY.

       +[no]tcp
              Use [do not use] TCP when querying name servers. The default be-
              havior is to use UDP unless a type any or ixfr=N  query  is  re-
              quested,  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
              This feature is related to dig +sigchase, which is obsolete  and
              has been removed. 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 de-
              fault queries from a nameserver.

       +tries=T
              Sets the number of times to try UDP queries to server to  T  in-
              stead 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=####
              Formerly specified trusted keys for use with dig +sigchase. This
              feature is now obsolete and has been removed; 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, min-
              utes, hours, days and weeks. Implies +ttlid.

       +[no]unexpected
              Accept  [do not accept] answers from unexpected sources.  By de-
              fault, dig won't accept a reply from a source other than the one
              to which it sent the query.

       +[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]yaml
              Print  the  responses  (and,  if <option>+qr</option> is in use,
              also the outgoing queries) in a detailed YAML format.

       +[no]zflag
              Set [do not set] the last unassigned DNS header flag  in  a  DNS
              query.  This flag is off by default.

MULTIPLE QUERIES
       The  BIND  9 implementation of dig supports specifying multiple queries
       on the command line (in addition to supporting the -f  batch  file  op-
       tion). 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 +[no]cmd and
       +[no]short options) 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.

IDN SUPPORT
       If dig has been built with IDN (internationalized domain name) support,
       it can accept and display non-ASCII  domain  names.  dig  appropriately
       converts  character encoding of domain name before sending a request to
       DNS server or displaying a reply from the server. If you'd like to turn
       off the IDN support for some reason, use parameters +noidnin and +noid-
       nout or define the IDN_DISABLE environment variable.

FILES
       /etc/resolv.conf

       ${HOME}/.digrc

SEE ALSO
       delv(1), host(1), named(8), dnssec-keygen(8), RFC 1035.

BUGS
       There are probably too many query options.

AUTHOR
       Internet Systems Consortium

COPYRIGHT
       2020, Internet Systems Consortium

9.16.8-Debian                     2020-10-13                            DIG(1)

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