Now that the new server is a DC, change its Preferred DNS to 127.0.0.1 (itself) and set the Alternate DNS to your first DC. Pro-Tip: The "Forgotten Step"
The wizard will grumble about "Physical Network Adapters" or "NT 4.0" compatibility. As long as you get the green checkmark at the top, hit Install . Phase 4: The Handshake The server will reboot automatically. Once it’s back up: Now that the new server is a DC,
Follow the wizard to and check Active Directory Domain Services . Click "Add Features" when prompted, then hit Install . then hit Install .