Install DNS Server role in Windows Essential Business Server
If you installed Windows EBS in an environment where DNS is not integrated with Active Directory Domain Services, you must install the DNS Server role on the Management Server and the Messaging Server.
For more information about the DNS Server role, see Windows Server 2008 Help: Click Start, and then click Help and Support.
You must perform the following procedure on the Management Server and the Messaging Server.
To install the DNS Server role
Log on to the server as domain administrator.
In Server Manager, click Add Roles.
In the Add Roles Wizard, follow the steps to add the DNS Server role.