You deploy an Active Directory domain named contoso.com to the network. The domain is configured as an Active Directory-integrated zone. All domain controllers
run Windows Server 2012 and are DNS servers.
You plan to deploy a child domain named operations.contoso.com.
You need to recommend changes to the DNS infrastructure to ensure that users in the operations department can access the servers in the contoso.com domain.
What should you include in the recommendation?
A.
A zone delegation for _msdcs.contoso.com
B.
Changes to the replication scope of contoso.com
C.
Changes to the replication scope of _msdcs.contoso.com
D.
Changes to the replication scope of operations.contoso.com
Explanation:
Manually Create a Delegation for the Child Domain on the Parent (Root) DNS Server
1. Right-click the root zone, click New Delegation, and then click Next.
2. Type the domain name for the child domain, and then click Next.
3. Add the child DNS server to host the new zone, and then click Next. NOTE: A domain controller that is a DNS server should have a static Transport Control
Protocol/Internet Protocol (TCP/IP) address. Verify that this step is performed before you install DNS on the child domain controller. If no DNS TCP/IP address
exists, DNS is installed as a root server. If you see that a “.” folder is created after you install DNS, you must remove the root configuration. For additional
information about how to do this, click the article number below to view the article in the Microsoft Knowledge Base:
229840 DNS Server’s Root Hints and Forwarder Pages Are Unavailable
4. On the child domain DNS server, right-click My Network Places, and then click Properties.
5. Right-click the appropriate local connection, and then click Properties.
6. Under Components checked are used by this connection, click Internet Protocol (TCP/IP), and then click Properties.
7. Click Use the following DNS server addresses:, and then type the TCP/IP address of the parent (root) DNS server.
How To Create a Child Domain in Active Directory and Delegate the DNS Namespace to the Child Domain
http://support.microsoft.com/kb/255248
Well, I guess it´s B because maybe the DNS zone replication for contoso.com, since the operations.contoso.com domain didn´t exist before, would be set to ¨Replicate only to DC´s in this domain”, i.e., DNS replication will only affect DNS servers belonging exclusively to the contoso.com.
Changing it to ¨Replicate to all DC´s in the forest” would make available the DNS information to the operations.contoso.com domain as well.
I believe that creating “A zone delegation for _msdcs.contoso.com”, apart from the fact that “_msdcs.contoso.com” is not a domain and therefore can´t be delegated, it wouldn´t fulfill the request “ensure that users in the operations department can access the servers in the contoso.com domain”
More info at:
https://social.technet.microsoft.com/Forums/systemcenter/en-US/4db4c311-7206-400c-8c12-85ad4bd3e166/dns-resolution-between-child-and-parent-domain?forum=winserverDS