$TTL 86400
@               86400   IN      SOA     dns.edu.    root.dns.edu. (
                        2008032701 ; serial
                        28800 ; refresh
                        14400 ; retry
                        3600000 ; expire
                        0 ; negative cache ttl
                        )

@		IN	NS		dns.edu.
1		IN 	PTR		r1.edu.
20		IN 	PTR		dns.edu.
30		IN	PTR		pc.edu.
	