$TTL 1D
@ IN SOA x.root-servers.net. root. (
  2024090801    ; serial
          1D    ; refresh
          1H    ; retry
          1W    ; expire
          3H )  ; minimum

.                   3600 IN NS   x.root-servers.net.
.                   3600 IN NS   y.root-servers.net.
.                   3600 IN NS   z.root-servers.net.
x.root-servers.net. 3600 IN A    172.18.1.4
y.root-servers.net. 3600 IN A    172.18.1.5
z.root-servers.net. 3600 IN A    172.18.1.6
x.root-servers.net. 3600 IN AAAA fd00::4
y.root-servers.net. 3600 IN AAAA fd00::5
z.root-servers.net. 3600 IN AAAA fd00::6

jp.                 3600 IN NS   x.dns.jp.
jp.                 3600 IN NS   y.dns.jp.
jp.                 3600 IN NS   z.dns.jp.
x.dns.jp.           3600 IN A    172.18.1.8
y.dns.jp.           3600 IN A    172.18.1.9
z.dns.jp.           3600 IN A    172.18.1.10
x.dns.jp.           3600 IN AAAA fd00::8
y.dns.jp.           3600 IN AAAA fd00::9
z.dns.jp.           3600 IN AAAA fd00::a

com.                3600 IN NS   x.gtld-servers.net.
com.                3600 IN NS   y.gtld-servers.net.
com.                3600 IN NS   z.gtld-servers.net.
x.gtld-servers.net. 3600 IN A    172.18.1.12
y.gtld-servers.net. 3600 IN A    172.18.1.13
z.gtld-servers.net. 3600 IN A    172.18.1.14
x.gtld-servers.net. 3600 IN AAAA fd00::c
y.gtld-servers.net. 3600 IN AAAA fd00::d
z.gtld-servers.net. 3600 IN AAAA fd00::e