Problem
Suppose you are a messaging administrator for Contoso. You have just deployed an Exchange Server and you are in the process of migrating from a third-party messaging solution. Some of the employee's mailboxes are already migrated to Exchange Server, but some of them are still located on the third-party solution. Your organization uses Contoso. local as the AD domain.
You want to create an accepted domain named contoso.com, where, at the moment of migration, some of the employee mailboxes are located on the company's Exchange Servers and some are located on the third-party solution. In the future, all recipients for that domain will be hosted in the Exchange organization. What type of accepted domain will you create?