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:
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.
<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.