$ORIGIN example.com.
$TTL 86400
@ IN SOA ns.example.com. hostmaster.example.com. (
2019070801
86400 3600 604800 300 )
IN NS ns.example.com.
IN NS ns1.example.net.
IN NS ns2.example.net.
IN A 192.0.2.2
IN AAAA 2001:db8::2
ns IN A 192.0.2.3
ns IN AAAA 2001:db8::3
* IN A 192.0.2.4
* IN A 192.0.2.5
www IN A 192.0.2.6
wWw IN A 192.0.2.7
sub IN NS ns.sub.example.com.
sub IN NS ns1.example.net.
sub IN NS ns2.example.net.
ns.sub IN A 192.0.2.4
ns.sub IN AAAA 2001:db8::4