Your network contains two Active Directory domains named contoso.com and adatum.com.
The network contains a server named Server1 that runs Windows Server 2012 R2. Server1 has the DNS Server
server role installed. Server1 has a copy of the contoso.com DNS zone.
You need to configure Server1 to resolve names in the adatum.com domain. The solution must meet the
following requirements:
Prevent the need to change the configuration of the current name servers that host zones for adatum.com.
Minimize administrative effort.
Which type of zone should you create?

A.
Secondary

B.
Stub

C.
Reverse lookup

D.
Primary

Explanation:

When a zone that this DNS server hosts is a stub zone, this DNS server is a source only for information about
the authoritative name servers for this zone. The zone at this server must be obtained from another DNS
server that hosts the zone. This DNS server must have network access to the remote DNS server to copy the
authoritative name server information about the zone.
A stub zone is a copy of a zone that contains only necessary resource records (Start of Authority (SOA), Name
Server (NS), and Address/Host (A) record) in the master zone and acts as a pointer to the authoritative name
server. The stub zone allows the server to forward queries to the name server that is authoritative for the
master zone without going up to the root name servers and working its way down to the server. While a stub
zone can improve performance, it does not provide redundancy or load sharing.

You can use stub zones to:
Keep delegated zone information current. By updating a stub zone for one of its child zones regularly, the
DNS server that hosts both the parent zone and the stub zone will maintain a current list of authoritative DNS
servers for the child zone.
Improve name resolution. Stub zones enable a DNS server to perform recursion using the stub zone’s list of
name servers, without having to query the Internet or an internal root server for the DNS namespace.
Simplify DNS administration. By using stub zones throughout your DNS infrastructure, you can distribute a list
of the authoritative DNS servers for a zone without using secondary zones. However, stub zones do not serve
the same purpose as secondary zones, and they are not an alternative for enhancing redundancy and load
sharing.
There are two lists of DNS servers involved in the loading and maintenance of a stub zone:
The list of master servers from which the DNS server loads and updates a stub zone. A master server may be
a primary or secondary DNS server for the zone. In both cases, it will have a complete list of the DNS servers
for the zone.
The list of the authoritative DNS servers for a zone. This list is contained in the stub zone using name server
(NS) resource records.
When a DNS server loads a stub zone, such as widgets. tailspintoys.com, it queries the master servers, which
can be in different locations, for the necessary resource records of the authoritative servers for the zone
widgets. tailspintoys.com. The list of master servers may contain a single server or multiple servers, and it can
be changed anytime.
http: //technet.microsoft.com/en-us/library/cc771898.aspx
http: //technet.microsoft.com/en-us/library/cc754190.aspx
http: //technet.microsoft.com/en-us/library/cc730980.aspx