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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
       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 given. The BIND 9 implementation of dig allows multi-
       ple 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. If no usable server addresses
       are found, dig sends the query to the local host.

       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 via ${HOME}/.digrc.
       This file is read and any options in it are  applied  before  the  com-
       mand-line  arguments.  The -r option disables this feature, for scripts
       that need predictable behavior.

       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 to 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  are
              tried.  If no usable addresses are found, dig sends 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 - ANY, A, MX, SIG, etc.
              type can be any valid query type. If no type  argument  is  sup-
              plied, dig performs a lookup for an A record.

OPTIONS
       -4     This option indicates that only IPv4 should be used.

       -6     This option indicates that only IPv6 should be used.

       -b address[#port]
              This option sets 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 ap-
              pending #port.

       -c class
              This option sets the query class. The default class is IN; other
              classes are HS for Hesiod records or CH for Chaosnet records.

       -f file
              This option sets batch mode, in which 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 it would be presented as a
              query to dig using the command-line interface.

       -k keyfile
              This option tells named to sign queries using TSIG using  a  key
              read  from  the  given  file.  Key  files can be generated using
              tsig-keygen. 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     This option enables memory usage debugging.

       -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.

       -q name
              This option specifies the domain name to query. This  is  useful
              to distinguish the name from other arguments.

       -r     This  option  indicates  that options from ${HOME}/.digrc should
              not be read. This is useful for scripts  that  need  predictable
              behavior.

       -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 NS or AAAA). The default query type is A, unless the  -x  op-
              tion  is  supplied to indicate a reverse lookup. A zone transfer
              can be requested by specifying a type of AXFR. When an incremen-
              tal  zone  transfer  (IXFR) is required, set the type to ixfr=N.
              The incremental zone transfer contains all 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 is displayed as described in RFC
              3597.

       -u     This option indicates that print query times should be  provided
              in microseconds instead of milliseconds.

       -v     This option prints the version number and exits.

       -x addr
              This  option  sets  simplified  reverse lookups, for mapping ad-
              dresses to names. The addr is an IPv4 address in  dotted-decimal
              notation,  or a colon-delimited IPv6 address. When the -x option
              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.

       -y [hmac:]keyname:secret
              This option signs queries using TSIG with the given  authentica-
              tion  key.   keyname  is  the name of the key, and secret is the
              base64-encoded shared secret. hmac is the name of the key  algo-
              rithm;  valid  choices  are  hmac-md5,  hmac-sha1,  hmac-sha224,
              hmac-sha256, hmac-sha384, or hmac-sha512. If hmac is not  speci-
              fied,  the default is hmac-md5; if MD5 was disabled, the default
              is hmac-sha256.

       NOTE:
          Only the -k option should be used, rather than the  -y  option,  be-
          cause  with -y the shared secret is supplied as a command-line argu-
          ment 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
              This option is a synonym for +[no]aaonly.

       +[no]aaonly
              This option sets the aa flag in the query.

       +[no]additional
              This  option  displays [or does not display] the additional sec-
              tion of a reply. The default is to display it.

       +[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. 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.

       +[no]all
              This option sets or clears all display flags.

       +[no]answer
              This option displays [or does not display] the answer section of
              a reply. The default is to display it.

       +[no]authority
              This option displays [or does not display] the authority section
              of a reply. The default is to display it.

       +[no]badcookie
              This  option  retries  the  lookup with a new server cookie if a
              BADCOOKIE response is received.

       +[no]besteffort
              This option attempts 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 restores the default
              buffer size.

       +[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.

       +[no]class
              This option displays [or does not display] the CLASS when print-
              ing the record.

       +[no]cmd
              This  option  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 a global effect;
              it cannot be set globally and then overridden  on  a  per-lookup
              basis. The default is to print this comment.

       +[no]comments
              This  option  toggles  the  display of some comment lines in the
              output, with information about the packet header and OPT pseudo-
              section,  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=####
              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
              +cookie.

              +cookie is also set when +trace is set to better emulate the de-
              fault queries from a nameserver.

       +[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 [omitted] or, in the DNSKEY case, the key ID is displayed
              as the replacement, e.g. [ key id = value ].

       +[no]defname
              This  option,  which  is deprecated, is treated as a synonym for
              +[no]search.

       +[no]dns64prefix
              Lookup IPV4ONLY.ARPA AAAA and print any DNS64 prefixes found.

       +[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.

       +domain=somename
              This option sets the search list to contain  the  single  domain
              somename,  as  if  specified  in  a domain directive in /etc/re-
              solv.conf, and enables search list processing as if the  +search
              option were given.

       +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  de-
              fault no code point is explicitly set.

       +[no]edns[=#]
              This option specifies the EDNS version to query with. Valid val-
              ues 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.

       +[no]ednsflags[=#]
              This option sets the must-be-zero EDNS flags bits  (Z  bits)  to
              the  specified value.  Decimal, hex, and octal encodings are ac-
              cepted. Setting a named flag (e.g., DO) is silently ignored.  By
              default, no Z bits are set.

       +[no]ednsnegotiation
              This  option  enables/disables  EDNS version negotiation. By de-
              fault, EDNS version negotiation is enabled.

       +[no]ednsopt[=code[:value]]
              This option specifies the EDNS option with code point  code  and
              an  optional  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
              This option sends an EDNS Expire option.

       +[no]fail
              This option indicates that named 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.

       +[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.

       +[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.

              If value is specified, it will be used as the HTTP  endpoint  in
              the  query  URI; the default is /dns-query. So, for example, dig
              @example.com   +https   will   use   the    URI    https://exam-
              ple.com/dns-query.

       +[no]https-get[=value]
              Similar to +https, except that the HTTP GET request mode is used
              when sending the query.

       +[no]https-post[=value]
              Same as +https.

       +[no]http-plain[=value]
              Similar to +https, except that HTTP queries will be sent over  a
              non-encrypted channel. When this option is in use, the port num-
              ber defaults to 80 and the HTTP request mode is POST.

       +[no]http-plain-get[=value]
              Similar to +http-plain, except that the  HTTP  request  mode  is
              GET.

       +[no]http-plain-post[=value]
              Same as +http-plain.

       +[no]identify
              This  option  shows  [or  does not show] the IP address and port
              number that supplied the answer, when the +short option  is  en-
              abled.  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
              This  option processes [or does 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
              This  option converts [or does 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
              This  option  ignores [or does not ignore] truncation in UDP re-
              sponses instead of retrying with TCP. By  default,  TCP  retries
              are performed.

       +[no]keepalive
              This option sends [or does not send] an EDNS Keepalive option.

       +[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 +nokeepopen.

       +[no]multiline
              This  option  prints  [or  does not print] records, like the SOA
              records, in a verbose multi-line format with human-readable com-
              ments.  The  default is to print each record on a single line to
              facilitate machine parsing of the dig output.

       +ndots=D
              This option sets the number of dots (D) that must appear in name
              for  it to be considered absolute. The default value is that de-
              fined using the ndots statement in /etc/resolv.conf, or 1 if  no
              ndots  statement  is  present.  Names with fewer dots are inter-
              preted as relative names, and are searched for  in  the  domains
              listed  in the search or domain directive in /etc/resolv.conf if
              +search is set.

       +[no]nsid
              When enabled, this option includes an EDNS name  server  ID  re-
              quest 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  did  not  respond  are  also
              printed.

       +[no]onesoa
              When  enabled, this option prints only one (starting) SOA record
              when performing an AXFR. The default is to print both the start-
              ing and ending SOA records.

       +[no]opcode=value
              When enabled, this option sets (restores) the DNS message opcode
              to the specified value. The default value is QUERY (0).

       +padding=value
              This option pads the size of the query  packet  using  the  EDNS
              Padding  option  to  blocks  of  value bytes. For example, +pad-
              ding=32 causes a 48-byte query to be padded to 64 bytes. The de-
              fault  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.

       +qid=value
              This option specifies the query ID to use when sending queries.

       +[no]qr
              This  option  toggles  the display of the query message as it is
              sent. By default, the query is not printed.

       +[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.

       +[no]raflag
              This option sets [or does not set] the RA (Recursion  Available)
              bit  in the query. The default is +noraflag. This bit is ignored
              by the server for QUERY.

       +[no]rdflag
              This option is a synonym for +[no]recurse.

       +[no]recurse
              This option toggles 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 option is used.

       +retry=T
              This  option  sets  the  number  of  times  to retry UDP and TCP
              queries to server to  T  instead  of  the  default,  2.   Unlike
              +tries, this does not include the initial query.

       +[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.

       +[no]search
              This option uses [or does 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  whether the name is treated as relative and
              hence whether a search is eventually performed.

       +[no]short
              This option toggles whether a terse answer is provided. The  de-
              fault  is to print the answer in a verbose form. This option al-
              ways has a global effect; it cannot be  set  globally  and  then
              overridden on a per-lookup basis.

       +[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.

       +[no]showsearch
              This  option performs [or does not perform] a search showing in-
              termediate results.

       +[no]sigchase
              This feature is now obsolete and has been removed; use delv  in-
              stead.

       +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 at all. The default is 56 characters,  or
              44 characters when multiline mode is active.

       +[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.

       +[no]subnet=addr[/prefix-length]
              This  option  sends [or does not send] an EDNS CLIENT-SUBNET op-
              tion 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]tcflag
              This option sets [or does not set] the TC  (TrunCation)  bit  in
              the  query. The default is +notcflag. This bit is ignored by the
              server for QUERY.

       +[no]tcp
              This option indicates whether to  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
              This  option  sets the timeout for a query to T seconds. The de-
              fault timeout is 5 seconds. An attempt to set T to less  than  1
              is silently set to 1.

       +[no]tls
              This  option  indicates  whether  to use DNS over TLS (DoT) when
              querying name servers. When this option is in use, the port num-
              ber defaults to 853.

       +[no]topdown
              This  feature is related to dig +sigchase, which is obsolete and
              has been removed. Use delv instead.

       +[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, dig 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.

              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 name server.

       +tries=T
              This  option sets the number of times to try UDP and TCP 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=####
              This  option  formerly  specified  trusted keys for use with dig
              +sigchase. This feature is now obsolete and  has  been  removed;
              use delv instead.

       +[no]ttlid
              This option displays [or does not display] the TTL when printing
              the record.

       +[no]ttlunits
              This option displays [or does not display] the TTL  in  friendly
              human-readable  time  units  of  s, m, h, d, and w, representing
              seconds, minutes, hours, days, and weeks. This implies +ttlid.

       +[no]unknownformat
              This option prints 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
              This option uses [or  does  not  use]  TCP  when  querying  name
              servers. This alternate syntax to +[no]tcp is provided for back-
              wards compatibility. The vc stands for "virtual circuit."

       +[no]yaml
              When enabled, this option prints the responses (and, if  +qr  is
              in use, also the outgoing queries) in a detailed YAML format.

       +[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.

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 represents 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 can 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
       does  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 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  +noidnin  and  +noidnout,  or  define  the
       IDN_DISABLE environment variable.

RETURN CODES
       dig return codes are:

       0      DNS response received, including NXDOMAIN status

       1      Usage error

       8      Couldn't open batch file

       9      No reply from server

       10     Internal error

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
       2022, Internet Systems Consortium

9.18.1-1ubuntu1.3-Ubuntu          2022-03-07                            DIG(1)
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