$TTL 3D
@ 	IN 	SOA 	ns.example.com. admin.example.com. (
			1
			8H
			2H
			4W
			1D)
@ 	IN 	NS 	ns.example.com.
101 	IN 	PTR 	www.example.com.
102 	IN 	PTR 	mail.example.com.
10 	IN 	PTR 	ns.example.com.
