Your company has a main office and a highly secure branch office. The network contains an Active Directory domain named contoso.com. The main office contains all of the domain controllers. A firewall filters all of the incoming traffic to each office. You plan to deploy additional domain controllers to the branch office. You need to identify a solution to allow replication traffic through the firewall between the branch office and the main office. What solution should you identify?
More than one answer choice may achieve the goal. Select the BEST answer. A. On the firewalls, open the ports used by Microsoft Remote Procedure Call (RPC).
B. Configure an SMTP site link between the main office and the branch office. On the firewalls, open the ports used by SMTP.
C. Configure the domain controllers in the branch office to use a single Microsoft Remote Procedure Call (RPC) port for replication. On the firewalls, open the port.
D. Implement IPSec between the domain controllers in the main office and the branch office. On the firewalls, open the ports used by IPSec.