We currently have ArcGIS 10.4.1 Server on a standalone server, with a web adapter in our DMZ. We are looking at upgrading to 10.5 and adding Portal as well as the GeoEvent server. I made a quick diagram of how we intend to set this up. This is with portal and server running on the same server, and two web adapters on one server, and the GeoEvent server also living in the DMZ. We're a fairly small shop, so there won't be a ton of action on any of the servers.
Is this the correct way to set this up?