Can I still use my JS-API-built webGIS-Client when switching to Enterprise-Environment with Portal?

[FlorianSteiner]

We currently plan to switch from an ArcGIS Server-Environment 10.3.1 to ArcGIS Enterprise 10.6.1. We would like to install Portal now, in order to be able to use these features in the future. However for now, we would like to keep using our Javascript-webGIS-client built with the JS-API, accessing ArcGIS-Services directly without using Portal.
The question is, whether we can federate Portal and Server now to enable the integrated windows authentication without the need for "named users" in Portal. In other words: Is it possible to use the windows authentication in Portal to use ArcGIS-Services from the ArcGIS Server via the JS-API directly? OR: Should we separate Server and Portal and enable the integrated windows authentication via Active Directory directly in ArcGIS Server. The latter would be equivalent to the current configuration.

Thanks for any advice or hint!

[FlorianSteiner · Accepted solution]

I was able to find the answer to my question online (http://enterprise.arcgis.com/en/portal/latest/administer/windows/about-using-your-server-with-portal...) and by help of the ESRI Support. Summary: It is possible to use a federated installation, but only for "public" content. Roles are only supported via named users. We will have to separate Server and Portal in order to be able to keep using our webGIS-Client with Active Direcotry-Authentication without named users.