CNAME+NS+SOA かつNS+SOA返答など。
1. whois
a. [Domain Name] BILIBILI.CO.JP g. [Organization] BILIBILI,CO,LTD. l. [Organization Type] corporation m. [Administrative Contact] YM25932JP n. [Technical Contact] TW188401JP p. [Name Server] ns3.dnsv3.com p. [Name Server] ns4.dnsv3.com s. [Signing Key] [State] Connected (2022/12/31) [Registered Date] 2014/12/11 [Connected Date] 2014/12/11 [Last Update] 2022/01/01 01:13:21 (JST)
2. history
おかしな返答の権威サーバー
bilibili.co.jp. 86400 IN NS ns3.dnsv3.com. bilibili.co.jp. 86400 IN NS ns4.dnsv3.com.
$ dig -t a bilibili.co.jp @ns4.dnsv3.com ; <<>> DiG 9.11.3-1ubuntu1.17-Ubuntu <<>> -t a bilibili.co.jp @ns4.dnsv3.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 44890 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;bilibili.co.jp. IN A ;; ANSWER SECTION: bilibili.co.jp. 600 IN CNAME bilibili.co.jp.w.cdngslb.com. ;; AUTHORITY SECTION: bilibili.co.jp. 86400 IN NS ns3.dnsv3.com. bilibili.co.jp. 86400 IN NS ns4.dnsv3.com. ;; Query time: 67 msec ;; SERVER: 61.151.180.48#53(61.151.180.48) ;; WHEN: Fri Apr 08 23:18:39 JST 2022 ;; MSG SIZE rcvd: 139
$ dig -t ns bilibili.co.jp
; <<>> DiG 9.11.3-1ubuntu1.17-Ubuntu <<>> -t ns bilibili.co.jp ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60471 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;bilibili.co.jp. IN NS ;; ANSWER SECTION: bilibili.co.jp. 462 IN CNAME bilibili.co.jp.w.cdngslb.com. ;; AUTHORITY SECTION: w.cdngslb.com. 273 IN SOA ns1.vip.cdngslb.com. root.cdngslb.com. 181010 3600 3600 360000 300 ;; Query time: 157 msec ;; SERVER: 210.188.224.10#53(210.188.224.10) ;; WHEN: Fri Apr 08 23:17:13 JST 2022 ;; MSG SIZE rcvd: 134