DNS/グルーレコード/arpa
　　TLD/arpa

$ dnsq ns 128.in-addr.arpa a.root-servers.net
2 128.in-addr.arpa:
410 bytes, 1+0+6+12 records, response, noerror
query: 2 128.in-addr.arpa
authority: in-addr.arpa 172800 NS a.in-addr-servers.arpa
authority: in-addr.arpa 172800 NS b.in-addr-servers.arpa
authority: in-addr.arpa 172800 NS c.in-addr-servers.arpa
authority: in-addr.arpa 172800 NS d.in-addr-servers.arpa
authority: in-addr.arpa 172800 NS e.in-addr-servers.arpa
authority: in-addr.arpa 172800 NS f.in-addr-servers.arpa
additional: a.in-addr-servers.arpa 172800 A 199.212.0.73
additional: b.in-addr-servers.arpa 172800 A 199.253.183.183
additional: c.in-addr-servers.arpa 172800 A 196.216.169.10
additional: d.in-addr-servers.arpa 172800 A 200.10.60.53
additional: e.in-addr-servers.arpa 172800 A 203.119.86.101
additional: f.in-addr-servers.arpa 172800 A 193.0.9.1