You are an Enterprise administrator for contoso.com. The corporate network of the company consists of a single Active Directory forest called contoso.com. The forest contains two domains. You want to configure another child domain called Branch3.contoso.com with two domain controllers having the DNS server role installed.

You want to put all the users and computers in the new branch office in the branch3.contoso.com domain.Which of the following options would you choose to implement a DNS infrastructure for the child domain to ensure resources in the root domain and child domains are accessible by fully qualified domain names?

You solution must also provide name resolution services in the event that a single server fails for a prolonged period of time and automatically recognize when new DNS servers are added to or removed from the contoso.com domain.

A.
Add conditional forwarders for contoso.com on both the domain controllers of branch3.contoso.com domain. Next create a standard primary zone for branch.contoso.com.

B.
On one of the domain controllers of branch3.contoso.com domain, create a standard primary zone for contoso.com. On the other domain controller, create a standard secondary zone for contoso.com.

C.
On both the domain controllers of branch3.contoso.com domain, modify the root hints to include the domain controllers for contoso.com. On one of domain controllers, create an Active Directory integrated zone for branch.contoso.com.

D.
On one of the domain controllers of branch3.contoso.com domain, create an Active Directory Integrated zone for branch3.contoso.com and create an Active Directory Integrated stub zone for contoso.com.

E.
None of the above.

Explanation:

To implement a DNS infrastructure for the child domain to ensure resources in the root domain and child domains are accessible by fully qualified domain names, you need to create an Active Directory Integrated zone for branch3.contoso.com on one of the domain controllers of branch3.contoso.com domain.

Active Directory Integrated zones, store their zone information within Active Directory instead of text files. The advantages of this new type of zone included using Active Directory replication for zone transfers and allowing resource records to be added or modified on any domain controller running DNS. In other words, all Active Directory Integrated zones are always primary zones as they contain writable copies of the zone database.This would ensure that the name resolution service will automatically recognize when new DNS servers are added to or removed from the contoso.com domain

You also need to create an Active Directory Integrated stub zone for contoso.com to ensure the name resolution services in the event that a single server fails for a prolonged period of time. It contains copies of all the resource records in the corresponding zone on the master name server.

A stub zone is like a secondary zone in that it obtains its resource records from other name servers (one or more master name servers). Stub zones can be used instead of secondary zones to reduce the amount of zone transfer traffic over the WAN link connecting the two companies. When Active Directory-integrated stub zones are hosted in separate sites, you can update them using a local list of master servers in each site.

Reference: DNS Stub Zones in Windows Server 2003
http://www.windowsnetworking.com/articles_tutorials/DNS_Stub_Zones.html

Reference: Host Name Resolution Overview
http://www.tech-faq.com/planning-and-implementing-a-dns-namespace.shtml