In this task, you move the DNS role from your existing servers or devices to the Management Server and Messaging Server.
If you already have a DNS server, you must move the DNS role to ensure that Windows EBS reliably performs name resolution. The specific migration steps depend on whether DNS was integrated with Active Directory Domain Services in your environment before you installed Windows EBS. This may not be required for some configurations.
To avoid temporary disruptions to network operations, you should migrate DNS to Windows EBS when network traffic is low.
For instructions about how to migrate DNS from several different server environments to Windows EBS, read the related whitepaper on the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=95814).