Open up your DNS server configuration on the promoted domain server.
In the pane to the right, right click and select "New other records"
Select "Service Location(SRV)" from the list
Next to Service type "_ldap"
Next to Protocol type "_tcp"
For priority, set it to 0
For Weight, set it to 100
The port number is 389
Under Host offering this service, type "yourserver.your.domain.com"
(where yourserver is your promoted domain controller)
The recently promoted domain server is named PDC02
The domain is internal.contoso.com