Your company has a single Active Directory domain named oaktree.com. All servers run Windows Server 2008. You have a public DNS server named Server1, and an e-mail server named Server2.
Client computers outside the company domain are unable to send e-mail messages to oaktree.com. You verify that the host (A) DNS record for Server2 is available to external client computers.
You need to ensure that Server2 can receive e-mail messages from external client computers. How should you configure the oaktree.com DNS zone?
A. Add a Mail Exchanger (MX) record for Server2.
B. Add a Mailbox (MB) record for Server2. Set the Mailbox Host setting to Server2.
C. Add a Canonical (CNAME) record that maps Server2 to oaktree.com.
D. Add a Service Location (SRV) record for Server2. Set the Service field to _smtp. Set the Protocol field to _tcp. Set the Port Number to 25.
