Your network contains an Active Directory forest named contoso.com.
The forest contains two domains named contoso.com and child.contoso.com and two sites named Site1 and Site2. The domains and the sites are configured as shown in following table.

When the link between Site1 and Site2 fails, users fail to log on to Site2.
You need to identify what prevents the users in Site2 from logging on to the child.contoso.com domain.
What should you identify?（）

Your network contains an Active Directory domain named contoso.com. The domain contains a single location named Site1. The domain contains a server named Server1 that has the DHCP Server server role installed.
All client computers receive their IPv4 configurations dynamically.
The domain will expand to include a second location named Site2. A server named Server2 will be deployed to Site2. Site1 and Site2 will connect to each other by using a WAN link.
You need to ensure that the clients in both sites receive their IPv4 configurations from Server1.
In the table below, identify which actions must be performed on each server. Make only one selection in each row. Each correct selection is worth one point.