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Manual Pages for 1 dig



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
       troubleshoot 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. Unlike earlier versions, the BIND 9
       implementation 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 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.
           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 appending "#<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.

       -i
           Do reverse IPv6 lookups using the obsolete RFC 1886 IP6.INT domain,
           which is no longer in use. Obsolete bit string label queries (RFC
           2874) are not attempted.

       -k keyfile
           Sign queries using TSIG using a key read from the given file. Key
           files can be generated using tsig-keygen(8). 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.

       -t type
           The resource record type to query. It can be any valid query type.

       -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 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 (but
           see also the -i option).

       -y [hmac:]keyname:secret
           Sign queries using TSIG with the given authentication key.  keyname
           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 ps(1) 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
       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
       +keyword=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

       +[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
           identifying the version of dig and the query options that have been
           applied. This comment is printed by default.

       +[no]comments
           Toggle the display of comment lines in the output. The default is
           to print comments.

       +[no]cookie[=####]
           Send a COOKIE EDNS option, with optional value. Replaying a COOKIE
           from a previous response will allow the server to identify 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
           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 version
           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 supplied
           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.

       +[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 format
           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.

       +[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).

       +[no]qr
           Print [do not print] the query as it is sent. By default, the query
           is not printed.

       +[no]question
           Print [do not print] the question section of a query when an answer
           is returned. The default is to print the question section as a
           comment.

       +[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.

           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.

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

       +[no]sigchase
           Chase DNSSEC signature chains. Requires dig be compiled with
           -DDIG_SIGCHASE. This feature is deprecated. 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 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 query option 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.

       +[no]subnet=addr[/prefix-length]
           Send (don't send) an EDNS Client Subnet option 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]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
           When chasing DNSSEC signature chains perform a top-down validation.
           Requires dig be compiled with -DDIG_SIGCHASE. This feature is
           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=####
           Specifies a file containing trusted keys to be used with +sigchase.
           Each DNSKEY record must be on its own line.

           If not specified, dig will look for /etc/trusted-key.key then
           trusted-key.key in the current directory.

           Requires dig be compiled with -DDIG_SIGCHASE. This feature is
           deprecated. 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,
           minutes, hours, days and weeks. Implies +ttlid.

       +[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]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
       standard options and flags, the name to be looked up, an optional query
       type and class and any query options that should be applied to that
       query.

       A global set of query options, which should be applied to all queries,
       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
       +noidnout.


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, Inc.


COPYRIGHT

       Copyright (C) 2000-2011, 2013-2018 Internet Systems Consortium, Inc.
       ("ISC")



ISC                               2014-02-19                            DIG(1)