$TTL 1D
@ IN SOA x.gtld-servers.net. root.com. (
  2024090801    ; serial
          1D    ; refresh
          1H    ; retry
          1W    ; expire
     2000000 )  ; minimum

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

test                3600 IN NS   ns1.test.com.
test                3600 IN NS   ns2.test.com.
ns1.test.com.       3600 IN A    172.18.1.20
ns2.test.com.       3600 IN A    172.18.1.21