watchNS/google.comについて、ここに記述してください。
$ dig -t ns google.com @ns4.google.com
; <<>> DiG 9.9.5-3ubuntu0.8-Ubuntu <<>> -t ns google.com @ns4.google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11265 ;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 4 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;google.com. IN NS ;; ANSWER SECTION: google.com. 345600 IN NS ns1.google.com. google.com. 345600 IN NS ns3.google.com. google.com. 345600 IN NS ns2.google.com. google.com. 345600 IN NS ns4.google.com. ;; ADDITIONAL SECTION: ns1.google.com. 345600 IN A 216.239.32.10 ns3.google.com. 345600 IN A 216.239.36.10 ns2.google.com. 345600 IN A 216.239.34.10 ns4.google.com. 345600 IN A 216.239.38.10 ;; Query time: 99 msec ;; SERVER: 216.239.38.10#53(216.239.38.10) ;; WHEN: Wed Jul 13 21:14:25 JST 2016 ;; MSG SIZE rcvd: 164
$ dig -t ns l.google.com @ns4.google.com
; <<>> DiG 9.9.5-3ubuntu0.8-Ubuntu <<>> -t ns l.google.com @ns4.google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38314 ;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 4 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;l.google.com. IN NS ;; ANSWER SECTION: l.google.com. 86400 IN NS ns4.google.com. l.google.com. 86400 IN NS ns3.google.com. l.google.com. 86400 IN NS ns2.google.com. l.google.com. 86400 IN NS ns1.google.com. ;; ADDITIONAL SECTION: ns4.google.com. 345600 IN A 216.239.38.10 ns3.google.com. 345600 IN A 216.239.36.10 ns2.google.com. 345600 IN A 216.239.34.10 ns1.google.com. 345600 IN A 216.239.32.10 ;; Query time: 96 msec ;; SERVER: 216.239.38.10#53(216.239.38.10) ;; WHEN: Wed Jul 13 21:14:35 JST 2016 ;; MSG SIZE rcvd: 166