You must delete them manually to allow DHCP to take care of all new records moving forward. DHCP will give that duplicate named client an IP, but it will not register it into DNS.Also, it will allevaite another issue – If DHCP is on a DC, it will not overwrite the original host record for a machine getting a new lease with an IP previoulsy belonging to another host. Quoted from the following link: “Name squatting occurs when a non-Windows-based computer registers in Domain Name System (DNS) with a name that is already registered to a computer running a Windows® operating system.For example, some folks believe that the DNS servers or other DCs not be running DHCP should be in it. Make sure that NO user accounts are in that group, either.
Since the DHCP server always assigns the dynamic IP addresses to the client computers which may change from time to time, and the DNS maintains the records of the information about the host names and their corresponding IP addresses, there must be some technology with the help of which the DNS server records can automatically get updated with the latest IP addresses that the DHCP server has assigned to the DHCP clients.=============================================================== When a client shuts down, and later returns past the lease time, it may get a different IP address.With the default settings, a duplicate A record gets registered by DHCP with the client’s new IP.With the help of DNS integration with the DHCP, you can simplify this task and can remarkably reduce the administrative overhead.Just like other DHCP administration configurations, even this one requires that you should use the Enterprise Admin or Domain Admin account credentials to make the changes.