When you disable Netlogons ability to register A records on your Global Catalog Server, you must manually register the gc._msdcs.<DnsForestName>.

The Netlogon service on a domain controller registers the following:

A record(s) for the DnsDomainName for a domain controller.

A record(s) for the gc._msdcs.DnsForestName, if the domain controller is also a global catalog.

If you use Regedt32 on a domain controller to navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters

and set value name RegisterDnsARecords, a REG_DWORD data type, to 0, it will prevent the registration of the above A records. If the domain controller is a Global Catalog Server, you must manually register the gc._msdcs.<DnsForestName> record in the appropriate DNS zone.

Example:

<b>   gc._msdcs.JSIINC.com     A      192.168.0.1</b> NOTE: You might consider setting this entry to 0 if DNS fails on an update of an A record, as this will cause DNS to stop updating.