Question about Active Directory Domain Services installation on Windows Server 2025

Assuming this will be the first domain controller in a new lab domain, use a working DNS server initially if you need name resolution before installing AD DS. Pointing to 127.0.0.1 won’t resolve anything until a DNS service is actually running on the VM.

A straightforward setup is:

1. Assign a static IP appropriate for the VM’s network, along with its subnet mask and gateway.
2. Install Active Directory Domain Services, then promote the server to a domain controller and include the DNS Server role.
3. After promotion and restart, verify that the server’s preferred DNS points to its own static IP address. For a single-DC lab, leave alternate DNS blank.
4. Configure external DNS servers as forwarders in DNS Manager, rather than putting them in the network adapter’s alternate DNS field.
5. Point your domain clients to the domain controller’s IP for DNS.

Loopback can work once DNS is installed, but using the server’s static IP makes this lab configuration clearer. Don’t use public DNS as an alternate on domain members: it cannot resolve your private AD records.

If you’re adding this VM to an existing domain, use an existing domain controller’s internal DNS from the start instead.