Your network contains a single Active Directory forest.
The forest contains two domain trees named contoso.com and fabrikam.com. You have an Exchange Server 2010 organization.
The e-mail addresses for the organization are configured as shown in the following table. You need to ensure that all outbound e-mail messages from fabrikam.com appear to originate fromcontoso.com.
Users in contoso.com must be able to send e-mail messages to users in fabrikam.com by using theaddress format alias@fabrikam.com.
What should you do first?()