If there is a problem with PTRs getting updated even after configuring credentials, please see this article: DHCP server processes expired PTR resource records in Windows Server 2003 . The use of Name Protection in the Windows Server® 2008 R2 operating system prevents name squatting by non-Windows-based computers.
To configure DHCP Option 081, you must look at the DHCP server properties, under the DNS Tab in DHCP properties. If you have Windows 2008 R2 or Windows 2012 R2, in addition to configuring the DNS tab to force registration, you still must configure credentials and add the server to the Dns Update Proxy group.
Despite it being a DHCP Option, it’s not found in a DHCP server, scope or class option. After configuring the above provedure, the credentials and Dns Update Proxy group configuratuion will not update current or delete duplicate records. If DHCP is on a Windows 2008 R2 DC, to protect the DC when using the Dns Update Proxy group, you must secure the group by running: dnscmd /config /Open Acl On Proxy Updates 0 Using “DHCP Name Protection.” will register A and PTR record on behalf of a client, and will prevent a workstation (non-Windows) Name Squatting, meaning using a name that another machine (non-Windows or Windows) client that DHCP already registered , from registering it’s name.
The use of Name Protection in the Windows Server® 2008 R2 operating system prevents name squatting by non-Windows-based computers.
“ DHCP Name Protection The DNSupdateproxy group must be secured if Name Protection is enabled on any IPv4 scope Credentials for DNS update should be configured if secure dynamic DNS update is enabled and the domain controller is on the same host as the DHCP server
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.=============================================================== 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.You can use the following registry subkey to modify the update interval: HKEY_LOCAL_MACHINE\SYSTEM\Current Control Set\Services\Tcpip\Parameters\Default Registration Refresh Interval Data type: REG_DWORD Range: 0x0 – 0x FFFFFFFF seconds Default value: 0x15180 (86,400 seconds = 24 hours) for Windows 2000 Professional Default value: 0x E10 (3,600 seconds = 1 hour) for Windows 2000 Server and Windows Advanced Server Scope: Affects all adaptors This specifies the time interval between DNS update registration updates.The default Time To Live (TTL) value used for dynamic registrations is 20 minutes.Therefore, even if they were to scavenge these records, assuming the time stamp has ever been reached, the machines will refresh themselves anyway!