name {ttl} addr-class PTR real name
7.0 IN PTR monet.Berkeley.Edu.
A Domain Name Pointer record, PTR, allows special names to point to some other location in the domain. The above example of a PTR record is used in setting up reverse pointers for the special IN-ADDR.ARPA domain. This line is from the example hosts.rev file. PTR records are needed by the gethostbyaddr function. Note the trailing ``.'' which prevents BIND from appending the current $ORIGIN to that domain name.