My organization currently has our ArcServer behind our firewall and is implementing a web server with Web Adaptor installed and configured on it for use with our ArcGIS Online Organization account in our DMZ. Without the Web Adaptor in the DMZ, we currently have to VPN into our network to allow the data in our web-maps to appear. I understand the Web Adaptor was created so resolve this specific issue. My question comes from the configuring of the web adaptor. I understand how to make the web adaptor communicate back into our network to interact with our ArcServer, however, I do not understand the communication from the Web Adaptor through our exterior firewall, to our ArcGIS Online accounts. When we open an external facing port for ArcGIS Online requests (rest urls for the data), what ip address do we make that port accessible to? Do we just open the port to any world wide web authenticated domain through ESRI, or are there specific ESRI cloud based server ip address where the authentication credentials are held when we log into AGOL that the requests for data come from?
I hope this question was posed in a way that makes sense.