$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