Hi,
I have this issue in our environment.
User request is been full fill through ISA proxy server. As per the current configuration Flex portal request redirect to port 80 for ArcGIS Server (Which is standard) but for Portal which is access through a tab in a sharepoint portal, request is redirected through a different port. Does these ports need to be same (same as ArcGIS Server standard port 80).
Thanks & Regards
Deep