Recently I had some cases where I had troubles with building/configuring ArcGIS for Server due to the ports used by ArcGIS for Server components and other security/backup softwares.
By default or by design, some of the ArcGIS for Server components use very specific ports which cannot be changed. For example, 6080/6443/7080/7443/2443/9876.
Some of our clients have already established their own enterprise system and it's very hard to change the enterprise system for just implementing ArcGIS for Server. Please let us change the ports used by ArcGIS for Server so that we can implement ArcGIS for Server without changing the customers enterprise system. I think an "enterprise software" should have this capability.