キャッシュされたサーバーをバイパスして、LinuxおよびMac OS Xコマンドラインから権限のあるDNSネームサーバーに直接クエリを実行するにはどうすればよいですか?
これは、権限のあるサーバーで新しく作成されたDNSホスト名をすぐに確認したい場合や、キャッシュされたDNSサーバーがTTLを「更新」/期限切れにするのを待ちたくない場合に役立ちます。
Dig
を使用すると、これを自動的に行うことができます。
$ Dig +trace www.google.com
; <<>> Dig 9.8.3-P1 <<>> +trace www.google.com
;; global options: +cmd
. 376983 IN NS c.root-servers.net.
. 376983 IN NS d.root-servers.net.
. 376983 IN NS l.root-servers.net.
. 376983 IN NS j.root-servers.net.
. 376983 IN NS f.root-servers.net.
. 376983 IN NS b.root-servers.net.
. 376983 IN NS i.root-servers.net.
. 376983 IN NS g.root-servers.net.
. 376983 IN NS a.root-servers.net.
. 376983 IN NS e.root-servers.net.
. 376983 IN NS k.root-servers.net.
. 376983 IN NS m.root-servers.net.
. 376983 IN NS h.root-servers.net.
;; Received 512 bytes from 172.16.0.1#53(172.16.0.1) in 2424 ms
com. 172800 IN NS a.gtld-servers.net.
com. 172800 IN NS l.gtld-servers.net.
com. 172800 IN NS i.gtld-servers.net.
com. 172800 IN NS k.gtld-servers.net.
com. 172800 IN NS g.gtld-servers.net.
com. 172800 IN NS m.gtld-servers.net.
com. 172800 IN NS f.gtld-servers.net.
com. 172800 IN NS h.gtld-servers.net.
com. 172800 IN NS e.gtld-servers.net.
com. 172800 IN NS j.gtld-servers.net.
com. 172800 IN NS d.gtld-servers.net.
com. 172800 IN NS c.gtld-servers.net.
com. 172800 IN NS b.gtld-servers.net.
;; Received 504 bytes from 192.36.148.17#53(192.36.148.17) in 4357 ms
google.com. 172800 IN NS ns2.google.com.
google.com. 172800 IN NS ns1.google.com.
google.com. 172800 IN NS ns3.google.com.
google.com. 172800 IN NS ns4.google.com.
;; Received 168 bytes from 192.33.14.30#53(192.33.14.30) in 503 ms
www.google.com. 300 IN A 173.194.127.240
www.google.com. 300 IN A 173.194.127.244
www.google.com. 300 IN A 173.194.127.242
www.google.com. 300 IN A 173.194.127.241
www.google.com. 300 IN A 173.194.127.243
;; Received 112 bytes from 216.239.32.10#53(216.239.32.10) in 164 ms
$ Host -t ns <domain>
信頼できるサーバー名を提供します。次に、以下を実行します。
$ Host <hostname> <authoritative_DNS_name>
authoritative_DNS_nameサーバーからのDNS変換を確認します。
Mac OSXの例を次に示します。同じコマンドがUbuntu12.04.2LTSで機能します。
desktop5-macos Jan 04 13:54:29 ~$ Host -t ns google.com
google.com name server ns3.google.com.
google.com name server ns1.google.com.
google.com name server ns2.google.com.
google.com name server ns4.google.com.
desktop5-macos Jan 04 13:54:31 ~$ Host google.com ns1.google.com
Using domain server:
Name: ns1.google.com
Address: 216.239.32.10#53
Aliases:
google.com has address 74.125.225.3
google.com has address 74.125.225.2
google.com has address 74.125.225.5
google.com has address 74.125.225.0
google.com has address 74.125.225.4
google.com has address 74.125.225.9
google.com has address 74.125.225.6
google.com has address 74.125.225.8
google.com has address 74.125.225.7
google.com has address 74.125.225.1
google.com has address 74.125.225.14
google.com has IPv6 address 2607:f8b0:4009:806::1005
google.com mail is handled by 40 alt3.aspmx.l.google.com.
google.com mail is handled by 50 alt4.aspmx.l.google.com.
google.com mail is handled by 20 alt1.aspmx.l.google.com.
google.com mail is handled by 10 aspmx.l.google.com.
google.com mail is handled by 30 alt2.aspmx.l.google.com.
desktop5-macos Jan 04 13:54:35 ~$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.7.4
BuildVersion: 11E53
desktop5-macos Jan 04 13:54:38 ~$