Enter the NetBIOS name or fully qualified domain name (FQDN) of the RemoteApp source. If you are using an RD Session Host ...

Enter the NetBIOS name or fully qualified domain name (FQDN) of the RemoteApp source.  If you are using an RD Session Host server farm as the RemoteApp source, specify the DNS name of the farm. If you are specifying multiple RemoteApp sources, separate each name with a semicolon.