== DNS/リゾルバー/JPサーバ ==
root-serversにJP NSを問い合わせると以下のような返事がえられる。
　ここでa.dns.jpなどはjpゾーン内の名前ではないことに注意。(あとで分かることだ）
　　additional sectionにあるIPアドレスを受け入れて、問い合わせを続けよう。
- ToshinoriMaeno <<DateTime(2016-10-17T09:59:56+0900)>>

[[../dns.jpを調べる]]

$ dig -t ns jp @a.root-servers.net
{{{
; <<>> DiG 9.9.5-3ubuntu0.9-Ubuntu <<>> -t ns jp @a.root-servers.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50173
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 7, ADDITIONAL: 14
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1472
;; QUESTION SECTION:
;jp.				IN	NS

;; AUTHORITY SECTION:
jp.			172800	IN	NS	a.dns.jp.
jp.			172800	IN	NS	b.dns.jp.
jp.			172800	IN	NS	c.dns.jp.
jp.			172800	IN	NS	d.dns.jp.
jp.			172800	IN	NS	e.dns.jp.
jp.			172800	IN	NS	f.dns.jp.
jp.			172800	IN	NS	g.dns.jp.

;; ADDITIONAL SECTION:
a.dns.jp.		172800	IN	A	203.119.1.1
b.dns.jp.		172800	IN	A	202.12.30.131
c.dns.jp.		172800	IN	A	156.154.100.5
d.dns.jp.		172800	IN	A	210.138.175.244
e.dns.jp.		172800	IN	A	192.50.43.53
f.dns.jp.		172800	IN	A	150.100.6.8
g.dns.jp.		172800	IN	A	203.119.40.1
a.dns.jp.		172800	IN	AAAA	2001:dc4::1
b.dns.jp.		172800	IN	AAAA	2001:dc2::1
c.dns.jp.		172800	IN	AAAA	2001:502:ad09::5
d.dns.jp.		172800	IN	AAAA	2001:240::53
e.dns.jp.		172800	IN	AAAA	2001:200:c000::35
f.dns.jp.		172800	IN	AAAA	2001:2f8:0:100::153

;; Query time: 63 msec
;; SERVER: 198.41.0.4#53(198.41.0.4)
;; WHEN: Mon Oct 17 09:57:20 JST 2016
;; MSG SIZE  rcvd: 427
}}}