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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 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/resolv.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
              serial number in the zone's SOA record was N.

              All  resource  record  types can be expressed as "TYPEnn", where
              "nn" is the number of the type. If the resource record  type  is
              not  supported  in  BIND  9,  the  result  will  be displayed as
              described in RFC 3597.

       -u     Print query times in microseconds instead of milliseconds.

       -v     Print the version number and exit.

       -x addr
              Simplified reverse lookups, for mapping addresses to names.  The
              addr  is  an  IPv4  address  in  dotted-decimal  notation,  or a
              colon-delimited IPv6 address. When the -x is used, there  is  no
              need  to  provide the name, class and type arguments.  dig 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
              default is hmac-md5 or if MD5 was disabled hmac-sha256.

       NOTE:
          You should use the -k option and avoid the -y option,  because  with
          -y the shared secret is supplied as a command line argument in clear
          text. This may be visible in the output from 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
       answer 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
       options are:

       +[no]aaflag
              A synonym for +[no]aaonly.

       +[no]aaonly
              Sets the "aa" flag in the query.

       +[no]additional
              Display  [do not display] the additional section of a reply. The
              default is to display it.

       +[no]adflag
              Set [do not set] the AD (authentic data) bit in the query.  This
              requests  the  server  to  return  whether all of the answer and
              authority sections have all been validated as  secure  according
              to  the  security  policy of the server. AD=1 indicates that all
              records have been validated as secure and the answer is not from
              a  OPT-OUT range. AD=0 indicate that some part of the answer was
              insecure or not validated.  This bit is set by default.

       +[no]all
              Set or clear all display flags.

       +[no]answer
              Display [do not display] the answer  section  of  a  reply.  The
              default is to display it.

       +[no]authority
              Display  [do  not display] the authority section of a reply. The
              default is to display it.

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

       +[no]besteffort
              Attempt to display the contents of messages which are malformed.
              The default is to not display malformed answers.

       +bufsize=B
              Set 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 will cause a EDNS
              query to be sent.

       +[no]cdflag
              Set [do not set] the CD (checking disabled) bit  in  the  query.
              This  requests  the  server  to not perform DNSSEC validation of
              responses.

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

       +[no]cmd
              Toggles the printing of the initial comment in the output, 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
              default queries from a nameserver.

       +[no]crypto
              Toggle  the  display  of cryptographic fields in DNSSEC records.
              The contents of these field are unnecessary to debug most DNSSEC
              validation failures and removing them makes it easier to see the
              common failures. The default is  to  display  the  fields.  When
              omitted  they  are  replaced by the string "[omitted]" or in the
              DNSKEY case the key id is displayed as the replacement, e.g.  "[
              key id = value ]".

       +[no]defname
              Deprecated, treated as a synonym for +[no]search

       +[no]dnssec
              Requests  DNSSEC  records  be  sent by setting the DNSSEC OK bit
              (DO) in the OPT record in the additional section of the query.

       +domain=somename
              Set the search list to contain the single domain somename, as if
              specified  in a domain directive in /etc/resolv.conf, and enable
              search list processing as if the +search option were given.

       +dscp=value
              Set the DSCP code point to be used when sending the query. Valid
              DSCP  code  points  are in the range [0..63]. By default no code
              point is explicitly set.

       +[no]edns[=#]
              Specify the EDNS version to query with. Valid values  are  0  to
              255.   Setting  the  EDNS  version will cause a EDNS query to be
              sent.  +noedns clears the remembered EDNS version. EDNS  is  set
              to 0 by default.

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

       +[no]ednsnegotiation
              Enable / disable EDNS version negotiation. By default EDNS  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
              option  name (for example, NSID or ECS), or an arbitrary numeric
              value. +noednsopt clears the EDNS options to be sent.

       +[no]expire
              Send an EDNS Expire option.

       +[no]fail
              Do not try the next  server  if  you  receive  a  SERVFAIL.  The
              default  is  to  not try the next server which is the reverse of
              normal stub resolver behavior.

       +[no]header-only
              Send a query with a DNS header without a question  section.  The
              default  is  to add a question section. The query type and query
              name are ignored when this is set.

       +[no]identify
              Show [or do not show] the IP address and port number  that  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
              requires IDN SUPPORT to have been enabled at compile time.

              The  default  is  to process IDN input when standard output is a
              tty.  The IDN processing on input is disabled when dig output is
              redirected  to files, pipes, and other non-tty file descriptors.

       +[no]idnout
              Convert [do not convert] puny code on output. This requires  IDN
              SUPPORT to have been enabled at compile time.

              The default is to process puny code on output when standard 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
              using  the ndots statement in /etc/resolv.conf, or 1 if no ndots
              statement is present. Names with fewer dots are  interpreted  as
              relative names and will be searched for in the domains listed in
              the search or domain directive in /etc/resolv.conf if +search is
              set.

       +[no]nsid
              Include an EDNS name server ID request when sending a query.

       +[no]nssearch
              When  this option is set, dig attempts to find the authoritative
              name servers for the zone containing the name  being  looked  up
              and  display  the  SOA  record that each name server has for the
              zone.  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
              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.

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

       +[no]question
              Toggles  the  display of the question section of a query when an
              answer is returned.  The default is to print the  question  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
              instead  of the default, 2. Unlike +tries, this does not include
              the initial query.

       +[no]rrcomments
              Toggle the display of per-record comments  in  the  output  (for
              example,  human-readable  key information about DNSKEY records).
              The default is not to print  record  comments  unless  multiline
              mode is active.

       +[no]search
              Use  [do  not  use] the search list defined by the searchlist or
              domain directive in resolv.conf (if any). The search list is not
              used by default.

              'ndots'  from resolv.conf (default 1) which may be overridden by
              +ndots determines if the name will be treated as relative or not
              and hence whether a search is eventually performed or not.

       +[no]short
              Provide a terse answer.  The default is to print the answer in a
              verbose form.  This option always has global effect;  it  cannot
              be set globally and then overridden on a per-lookup basis.

       +[no]showsearch
              Perform  [do not perform] a search showing intermediate results.

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

       +split=W
              Split  long  hex- or base64-formatted fields in resource records
              into chunks of W characters (where W is rounded up to the  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
              default  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
              behavior  is  to  use  UDP  unless a type any or ixfr=N query is
              requested, in which case the default is TCP. AXFR queries always
              use TCP.

       +timeout=T
              Sets  the  timeout for a query to T seconds. The default timeout
              is 5 seconds. An attempt to set T to less than 1 will result  in
              a query timeout of 1 second being applied.

       +[no]topdown
              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
              default queries from a nameserver.

       +tries=T
              Sets  the  number  of  times  to  try UDP queries to server to T
              instead of the default, 3. If T is less than or equal  to  zero,
              the number of tries is silently rounded up to 1.

       +trusted-key=####
              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
              default, 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
       option).  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



9.16.4                            2020-06-10                            dig(1)

bind 9.16.4 - Generated Thu Jun 18 09:17:01 CDT 2020
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