watchNS/mediatv.ne.jpについて、ここに記述してください。
1. JP 登録、返答
%dnsq a ns.mediatv.ne.jp a.dns.jp
1 ns.mediatv.ne.jp: 108 bytes, 1+0+2+2 records, response, noerror query: 1 ns.mediatv.ne.jp authority: mediatv.ne.jp 86400 NS ns.at-link.ad.jp authority: mediatv.ne.jp 86400 NS ns.mediatv.ne.jp additional: ns.mediatv.ne.jp 86400 A 61.206.45.168 additional: ns.at-link.ad.jp 86400 A 210.239.46.2
%dnsq a ns.mediatv.ne.jp 61.206.45.168
1 ns.mediatv.ne.jp: 92 bytes, 1+1+2+0 records, response, authoritative, weird ra, noerror query: 1 ns.mediatv.ne.jp answer: ns.mediatv.ne.jp 86400 A 61.206.45.168 authority: mediatv.ne.jp 86400 NS ns.mediatv.ne.jp authority: mediatv.ne.jp 86400 NS ns.at-link.ad.jp
%dig -t a www.qmail.jp @61.206.45.168
; <<>> DiG 9.9.0 <<>> -t a www.qmail.jp @61.206.45.168 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42300 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;www.qmail.jp. IN A ;; ANSWER SECTION: www.qmail.jp. 86400 IN A 14.192.44.5 ;; AUTHORITY SECTION: qmail.jp. 86400 IN NS a.ns.qmail.jp. ;; Query time: 31 msec ;; SERVER: 61.206.45.168#53(61.206.45.168) ;; WHEN: Sun May 10 21:49:06 2015 ;; MSG SIZE rcvd: 76
%dig -t a www.mediatv.ne.jp @61.206.45.168
; <<>> DiG 9.9.0 <<>> -t a www.mediatv.ne.jp @61.206.45.168 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15720 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;www.mediatv.ne.jp. IN A ;; ANSWER SECTION: www.mediatv.ne.jp. 86400 IN CNAME ns.mediatv.ne.jp. ns.mediatv.ne.jp. 86400 IN A 61.206.45.168 ;; AUTHORITY SECTION: mediatv.ne.jp. 86400 IN NS ns.mediatv.ne.jp. mediatv.ne.jp. 86400 IN NS ns.at-link.ad.jp. ;; Query time: 7 msec ;; SERVER: 61.206.45.168#53(61.206.45.168) ;; WHEN: Sun May 10 21:51:55 2015 ;; MSG SIZE rcvd: 121
外部NSのAを問い合せてみると、
%dig -t a ns.at-link.ad.jp @61.206.45.168
; <<>> DiG 9.9.0 <<>> -t a ns.at-link.ad.jp @61.206.45.168 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56564 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;ns.at-link.ad.jp. IN A ;; ANSWER SECTION: ns.at-link.ad.jp. 3600 IN A 210.239.46.2 ;; AUTHORITY SECTION: at-link.ad.jp. 3600 IN NS dns3.at-link.ad.jp. at-link.ad.jp. 3600 IN NS ns.at-link.ad.jp. ;; Query time: 19 msec ;; SERVER: 61.206.45.168#53(61.206.45.168) ;; WHEN: Sun May 10 21:52:46 2015 ;; MSG SIZE rcvd: 94
%dig -t a www.mediatv.ne.jp @61.206.45.168
; <<>> DiG 9.9.0 <<>> -t a www.mediatv.ne.jp @61.206.45.168 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35912 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;www.mediatv.ne.jp. IN A ;; ANSWER SECTION: www.mediatv.ne.jp. 86400 IN CNAME ns.mediatv.ne.jp. ns.mediatv.ne.jp. 86400 IN A 61.206.45.168 ;; AUTHORITY SECTION: mediatv.ne.jp. 86400 IN NS ns.mediatv.ne.jp. mediatv.ne.jp. 86400 IN NS ns.at-link.ad.jp. ;; ADDITIONAL SECTION: ns.at-link.ad.jp. 3590 IN A 210.239.46.2 ;; Query time: 7 msec ;; SERVER: 61.206.45.168#53(61.206.45.168) ;; WHEN: Sun May 10 21:52:56 2015 ;; MSG SIZE rcvd: 137
2. 非再帰検索でも
%dnsq a www.mediatv.ne.jp 61.206.45.168
1 www.mediatv.ne.jp: 126 bytes, 1+2+2+1 records, response, authoritative, weird ra, noerror query: 1 www.mediatv.ne.jp answer: www.mediatv.ne.jp 86400 CNAME ns.mediatv.ne.jp answer: ns.mediatv.ne.jp 86400 A 61.206.45.168 authority: mediatv.ne.jp 86400 NS ns.mediatv.ne.jp authority: mediatv.ne.jp 86400 NS ns.at-link.ad.jp additional: ns.at-link.ad.jp 3569 A 210.239.46.2
additional に注目。ゴミだが、受け入れるリゾルバーもあるだろう。危険。