Decommission the existing DNS server
Decommission your existing DNS server to ensure that no computers on your network use it, which would create a split-DNS scenario. You can decommission your existing DNS server in various ways. Follow these steps to stop and disable the service (disabling the service is advised to ensure that the service does not start if the server is restarted).
If your DNS server is not running a Windows Server operating system, consult documentation to determine how to decommission it.
Follow these steps to decommission your existing DNS server:
To stop and disable service on your DNS server
Log on to your existing DNS server as domain administrator.
To open the Services console, click Start, click Run, type services.msc, and then click OK.
Right-click DNS Server, and then click Stop.
Right-click DNS Server again, and then click Properties. On the General tab, in Startup type, click Disabled, and then click OK.
Follow these steps if you joined Windows EBS to an existing domain:
To delete records from DNS
Log on to your Management Server as domain administrator.
To open the DNS console, click Start, click Administrative Tools, and then click DNS.
In the DNS console, browse the forward and reverse zones, and delete records of computers that have been decommissioned or no longer exist.