Summery
DNSサーバーが正常に動作しているか確認する。
Domain Information Groper（ドメイン情報探索ツール）
Construction
$ dig [option] [name-server] domain [type] [option]
Option
# DIGコマンドオプション
retry=# : 再試行の回数を#に設定する
time=# : タイムアウト時間を#秒に設定する
-x : 逆アドレス変換を指定する
+answer : Answerセクションのみ表示する（+noallと併用）
+multiline : 出力結果を整形する
+noall : 何も表示しない
+norecurse : 再帰問い合わせしない
+stats : 問い合わせの統計を表示する
+trace : ルートDNSから問い合わせを行い、結果を順番に出力する
# クエリタイプ
A : ネットワークアドレス
ANY : 指定されたドメインの全情報
HINFO : ホスト情報
MX : メールアドレスに使用するドメイン名
NS : ゾーン権限を持つネームサーバー
SOA : ゾーン情報が記述されたレコード
TXT : 任意の文字列
# クエリオプション
-4 : IPv4で問い合わせる
-6 : IPv6で問い合わせる（接続不可の場合はIPv4）
-p # : ポート番号を#に指定する
Sample
# ドメインの情報を表示
$ dig google.com
; < <>> DiG 9.8.3-P1 < <>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER< <- opcode: QUERY, status: NOERROR, id: 64321
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 300 IN A 216.58.220.206
;; AUTHORITY SECTION:
google.com. 145616 IN NS ns3.google.com.
google.com. 145616 IN NS ns4.google.com.
google.com. 145616 IN NS ns2.google.com.
google.com. 145616 IN NS ns1.google.com.
;; ADDITIONAL SECTION:
ns1.google.com. 145616 IN A 216.239.32.10
ns2.google.com. 145616 IN A 216.239.34.10
ns3.google.com. 145616 IN A 216.239.36.10
ns4.google.com. 145616 IN A 216.239.38.10
;; Query time: 53 msec
;; SERVER: 192.168.1.17#53(192.168.1.17)
;; WHEN: Wed Mar 18 23:32:10 2015
;; MSG SIZE rcvd: 180
Discription
NAME
dig - DNS lookup utility
SYNOPSIS
dig [@server] [-b address] [-c class] [-f filename] [-k filename] [-m]
[-p port#] [-q name] [-t type] [-x addr] [-y [hmac:]name:key] [-4] [-6]
[name] [type] [class] [queryopt...]
dig [-h]
dig [global-queryopt...] [query...]
DESCRIPTION
dig (domain information groper) 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.
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 domains
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 and
queries the name servers listed there. 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 supplied, dig will
perform a lookup for an A record.
OPTIONS
The -b option sets the source IP address of the query to address. This 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>"
The default query class (IN for internet) is overridden by the -c option.
class is any valid class, such as HS for Hesiod records or CH for Chaosnet
records.
The -f option makes dig operate in batch mode by reading a list of lookup
requests to process from the file filename. The file contains a number of
queries, one per line. Each entry in the file should be organized in the
same way they would be presented as queries to dig using the command-line
interface.
The -m option enables memory usage debugging.
If a non-standard port number is to be queried, the -p option is used.
port# is the port number that dig will send its queries instead of the
standard DNS port number 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.
The -4 option forces dig to only use IPv4 query transport. The -6 option
forces dig to only use IPv6 query transport.
The -t option sets the query type to type. It can be any valid query type
which is supported in BIND 9. The default query type is "A", unless the -x
option is supplied to indicate a reverse lookup. A zone transfer can be
requested by specifying a type of AXFR. When an incremental zone transfer
(IXFR) is required, type is set 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.
The -q option sets the query name to name. This useful do distinguish the
name from other arguments.
Reverse lookups -- mapping addresses to names -- are simplified by the -x
option. addr is an IPv4 address in dotted-decimal notation, or a
colon-delimited IPv6 address. When this option is used, there is no need to
provide the name, class and type arguments. dig automatically performs a
lookup for a name like 11.12.13.10.in-addr.arpa and sets the query type and
class to PTR and IN respectively. By default, IPv6 addresses are looked up
using nibble format under the IP6.ARPA domain. To use the older RFC1886
method using the IP6.INT domain specify the -i option. Bit string labels
(RFC2874) are now experimental and are not attempted.
To sign the DNS queries sent by dig and their responses using transaction
signatures (TSIG), specify a TSIG key file using the -k option. You can
also specify the TSIG key itself on the command line using the -y option;
hmac is the type of the TSIG, default HMAC-MD5, name is the name of the
TSIG key and key is the actual key. The key is a base-64 encoded string,
typically generated by dnssec-keygen(8). Caution should be taken when using
the -y option on multi-user systems as the key can be visible in the output
from ps(1) or in the shell's history file. 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.
Mac OS X NOTICE
The dig command does not use the host name and address resolution or the
DNS query routing mechanisms used by other processes running on Mac OS X.
The results of name or address queries printed by dig may differ from those
found by other processes that use the Mac OS X native name and address
resolution mechanisms. The results of DNS queries may also differ from
queries that use the Mac OS X DNS routing library.
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. The
query options are:
+[no]tcp
Use [do not use] TCP when querying name servers. The default behavior
is to use UDP unless an AXFR or IXFR query is requested, in which case
a TCP connection is used.
+[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]ignore
Ignore truncation in UDP responses instead of retrying with TCP. By
default, TCP retries are performed.
+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.
+[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.
+[no]showsearch
Perform [do not perform] a search showing intermediate results.
+[no]defname
Deprecated, treated as a synonym for +[no]search
+[no]aaonly
Sets the "aa" flag in the query.
+[no]aaflag
A synonym for +[no]aaonly.
+[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.
+[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]cl
Display [do not display] the CLASS when printing the record.
+[no]ttlid
Display [do not display] the TTL when printing the record.
+[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.
+[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]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.
+[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]short
Provide a terse answer. The default is to print the answer in a verbose
form.
+[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]comments
Toggle the display of comment lines in the output. The default is to
print comments.
+[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]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]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]additional
Display [do not display] the additional section of a reply. The default
is to display it.
+[no]all
Set or clear all display flags.
+time=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.
+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.
+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.
+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.
+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.
+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.
+[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.
+[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]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]besteffort
Attempt to display the contents of messages which are malformed. The
default is to not display malformed answers.
+[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.
+[no]sigchase
Chase DNSSEC signature chains. Requires dig be compiled with
-DDIG_SIGCHASE.
+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.
+[no]topdown
When chasing DNSSEC signature chains perform a top-down validation.
Requires dig be compiled with -DDIG_SIGCHASE.
+[no]nsid
Include an EDNS name server ID request when sending a query.
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, 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 the +[no]cmd option) 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, defines the IDN_DISABLE environment variable. The
IDN support is disabled if the variable is set when dig runs.
FILES
/etc/resolv.conf
${HOME}/.digrc
SEE ALSO
host(1), named(8), dnssec-keygen(8), RFC1035.
BUGS
There are probably too many query options.
COPYRIGHT
Copyright (C) 2004-2010 Internet Systems Consortium, Inc. ("ISC")
Copyright (C) 2000-2003 Internet Software Consortium.
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