Change the Priority for DNS Service (SRV) Resource Records in the Registry
Applies To: Windows Server 2008, Windows Server 2008 R2
You can use this procedure to reduce the workload on the primary domain controller (PDC) emulator operations master by changing the priority for Domain Name System (DNS) service (SRV) resource records in the registry.
Registry Editor bypasses standard safeguards, which allows settings that can damage your system or even require you to reinstall Windows. If you must edit the registry, back up critical volumes first. For information about backing up critical volumes, see Administering Active Directory Backup and Recovery.
Membership in Domain Admins, or equivalent, is the minimum required to complete this procedure. Review details about using the appropriate accounts and group memberships at Local and Domain Default Groups (http://go.microsoft.com/fwlink/?LinkId=83477).
To change the priority for DNS SRV records in the registry
Open Registry Editor as an administrator: Click Start and then, in Start Search, type regedit. At the top of the Start menu, right-click regedit, and then click Run as administrator. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
In Registry Editor, navigate to HKLM\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters.
Click Edit, click New, and then click DWORD (32-BIT) Value.
For the new value name, type LdapSrvPriority, and then press ENTER.
Double-click the value name that you just typed to open the Edit DWORD (32-BIT) Value dialog box.
Enter a value from 0 through 65535. The default value is 0.
Choose Decimal as the Base option, and then click OK.
Click File, and then click Exit to close Registry Editor.