watchNS/coara.or.jpについて、ここに記述してください。

$ dnsq ns coara.or.jp a.dns.jp

2 coara.or.jp:
88 bytes, 1+0+2+1 records, response, noerror
query: 2 coara.or.jp
authority: coara.or.jp 86400 NS dns2.odn.ne.jp
authority: coara.or.jp 86400 NS ns.coara.or.jp
additional: ns.coara.or.jp 86400 A 192.244.1.1

$ dnsq any coara.or.jp ns.coara.or.jp

255 coara.or.jp:
217 bytes, 1+5+0+3 records, response, authoritative, weird ra, noerror
query: 255 coara.or.jp
answer: coara.or.jp 300 SOA ns.coara.or.jp root.coara.or.jp 2012080700 10800 3600 604800 300
answer: coara.or.jp 300 NS ns2.coara.or.jp
answer: coara.or.jp 300 NS ns.coara.or.jp
answer: coara.or.jp 300 NS dns2.odn.ne.jp
answer: coara.or.jp 300 PTR 0.1.244.192.in-addr.arpa
additional: ns.coara.or.jp 300 A 192.244.1.1
additional: ns2.coara.or.jp 300 A 210.252.128.8
additional: dns2.odn.ne.jp 79678 A 143.90.130.57

こういうPTRレコードの使い方には意味があるのだろうか。

$ dnsq any coara.or.jp ns2.coara.or.jp

255 coara.or.jp:
217 bytes, 1+5+0+3 records, response, authoritative, weird ra, noerror
query: 255 coara.or.jp
answer: coara.or.jp 300 SOA ns.coara.or.jp root.coara.or.jp 2012080700 10800 3600 604800 300
answer: coara.or.jp 300 NS dns2.odn.ne.jp
answer: coara.or.jp 300 NS ns.coara.or.jp
answer: coara.or.jp 300 NS ns2.coara.or.jp
answer: coara.or.jp 300 PTR 0.1.244.192.in-addr.arpa
additional: ns.coara.or.jp 300 A 192.244.1.1
additional: ns2.coara.or.jp 300 A 210.252.128.8
additional: dns2.odn.ne.jp 79849 A 143.90.130.57

返事するようになった。

$ dnsq any coara.or.jp dns2.odn.ne.jp

255 coara.or.jp:
217 bytes, 1+5+0+3 records, response, authoritative, weird ra, noerror
query: 255 coara.or.jp
answer: coara.or.jp 300 SOA ns.coara.or.jp root.coara.or.jp 2012083000 10800 3600 604800 300
answer: coara.or.jp 300 PTR 0.1.244.192.in-addr.arpa
answer: coara.or.jp 300 NS ns2.coara.or.jp
answer: coara.or.jp 300 NS dns2.odn.ne.jp
answer: coara.or.jp 300 NS ns.coara.or.jp
additional: ns.coara.or.jp 300 A 192.244.1.1
additional: ns2.coara.or.jp 300 A 210.252.128.8
additional: dns2.odn.ne.jp 1960 A 143.90.130.57

$ dnsq any 0.1.244.192.in-addr.arpa ns.coara.or.jp

255 0.1.244.192.in-addr.arpa:
237 bytes, 1+2+4+4 records, response, authoritative, weird ra, noerror
query: 255 0.1.244.192.in-addr.arpa
answer: 0.1.244.192.in-addr.arpa 400 PTR coara-net.coara.or.jp
answer: 0.1.244.192.in-addr.arpa 400 A 255.255.255.0
authority: 1.244.192.in-addr.arpa 400 NS ns.coara.or.jp
authority: 1.244.192.in-addr.arpa 400 NS dns2.odn.ne.jp
authority: 1.244.192.in-addr.arpa 400 NS ns2.coara.or.jp
authority: 1.244.192.in-addr.arpa 400 NS dns3.odn.ne.jp
additional: ns.coara.or.jp 300 A 192.244.1.1
additional: ns2.coara.or.jp 300 A 210.252.128.8
additional: dns2.odn.ne.jp 60496 A 143.90.130.57
additional: dns3.odn.ne.jp 59853 A 143.90.130.58