PTR (domain name pointer) resource record
PTR allows special names
to point to some other location in the domain.
The following 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 mynet.rev file.
In this record, the ``name'' field is the network
number of the host in reverse order. You only need to specify enough
octets to make the name unique. For example, if all hosts are on network
132.147.118, then only the last octet needs to be specified. If hosts are
on networks 132.147.118 and 132.147.246, then the last two octets need to be
specified.
PTR records are needed by gethostbyaddr(SLIB). Note the trailing ''.'', which prevents the appending of the current $ORIGIN.
PTR names should be unique to the zone.
Here is an example of a PTR record:
name {ttl} addr-class PTR real name 3.118 IN PTR thames.mynet.COM.