Creating an Additional Domain controller
This is same as creating a new DC for a new forest except small change where we have to select new DC to an existing the forest.
Goto “run” -> type “dcpromo.exe” click Next.
For a new DC in a new forest select “ Create a new domain in a new forest “ and click “next”.
Provide network credentials(for example “hyaking.com”) click Next.
Select DNS server as additional option for this server.
Provide location for database, log files & SYSVOL folders on local server and click Next.
Authenticate by providing the password and click Next.
Check the summary of the procedure and check the details and click Next to continue.
This will continue the installation of Active Directory service and reboot the server on completion.
This server acts as a additional Domain controller for any Local network if Primary Domain Controller is at other location provided there should be a Site-to-Site VPN tunnel established between two locations.