1. whois
2. history
fpu.ac.jp. 86400 IN NS dns4.fpu.ac.jp. fpu.ac.jp. 86400 IN NS dns3.fpu.ac.jp. fpu.ac.jp. 86400 IN NS dns.fpu.ac.jp. fpu.ac.jp. 86400 IN NS dns2.fpu.ac.jp. ;; ADDITIONAL SECTION: dns4.fpu.ac.jp. 86400 IN A 202.238.55.52 dns3.fpu.ac.jp. 86400 IN A 202.238.55.51 dns2.fpu.ac.jp. 86400 IN A 157.6.16.2 dns.fpu.ac.jp. 86400 IN A 157.6.16.3 51.55.238.202.in-addr.arpa. 3600 IN PTR 202-238-055-051.pool.mitene.or.jp. 52.55.238.202.in-addr.arpa. 3600 IN PTR 202-238-055-052.pool.mitene.or.jp.
$ dig -t ns fpu.ac.jp @202.238.55.51 ;; communications error to 202.238.55.51#53: timed out ;; communications error to 202.238.55.51#53: timed out ;; communications error to 202.238.55.51#53: timed out ; <<>> DiG 9.18.12-0ubuntu0.22.04.1-Ubuntu <<>> -t ns fpu.ac.jp @202.238.55.51 ;; global options: +cmd ;; no servers could be reached tmaeno@conoha:~/jp/at/ns/in$ dig -t ns fpu.ac.jp @202.238.55.52 ;; communications error to 202.238.55.52#53: timed out ;; communications error to 202.238.55.52#53: timed out ;; communications error to 202.238.55.52#53: timed out ; <<>> DiG 9.18.12-0ubuntu0.22.04.1-Ubuntu <<>> -t ns fpu.ac.jp @202.238.55.52 ;; global options: +cmd ;; no servers could be reached