Also, PTR resource records are commonly used by some applications to verify the identities of clients.
The following sections explain where to put reverse lookup zones and how to create, configure, and delegate them.
I just manually deleted any old entries that were not uptodate. I have triple entries on the same IP and all 3 entries are wrong (they don't match the forward at all).I deleted an entry from the reverse on a machine that receives DHCP, but after 2 days, it has not re added the machine into reverse DNS.Then I deleted all entries and restarted all the machines (of course I set the lease time to 1 day, one day prior to do the deletion).It fixed the forward DNS entries for the most part.
For information about any of the IP addressing concepts discussed in the following sections, see "Introduction to TCP/IP" in this book.To determine where to place your reverse lookup zones, first gather a list of all the subnets in your network, and then examine the class (A, B, or C) and type (class-based or subnetted) of each subnet.