DNS Question

forward lookup zone and reverse lookup zone for dns has multiple entries for one IP. What is the best way to cleanup DNS and DHCP?
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There are several options in DHCP to help with this issue.  Open the DHCP MMC, right click on your server and select properties, then click the DNS tab.

Enable these three options:
1) Enable DNS dynamic updates, etc...
2) Discard A and PTR records whe lease is deleted.
3) Dynamically update DNS A and PTR records for DHCP clients that do not request updates

Click OK and close DHCP MMC

In the DNS MMC go to properties of the desired zone(s), on the general tab you can set Aging/scavenging properties.
DrDave242Senior Support EngineerCommented:
ran into a similar problem once. When clients are disabled in Active Directory, (instead of deleted), they hold onto the DNS record. For some reason disabling clients keeps the DHCP lease active and therefor the DNS record. Once I deleted old computers from AD, those multiple DNS records for the same IP go away immediately.

If the client is disabled, the lease may be assigned to the next computer, then the next one. etc...

You see, when a DHCP lease is offered, a client should go perform a ping to see if the lease is active, before excepting the lease. Then, if multiple clients have that same IP and are registered within DNS, These records never end up scavaged because the clients are disabled (not deleted).

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Windows Server 2003

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