I apologize for the lengthy post - I'm not sure how to pare it down and be clear.
I'm using a Web Filter 410 to provide content filtering for 200 iPads. I'm not able to use the Barracuda Safe Browser for a couple of reasons, so I've pushed out a configuration profile to the iPads to use the Web Filter as a global proxy. I'm currently using a captive web portal to force users to authenticate. I initially made the mistake of not requiring authentication and it didn't take long for the world to start using my open proxy.
My problem is that some users are having trouble with the captive web portal from their home WiFi or from hotels and other locations. My question is whether I can still require authentication without using the captive web portal - I can include generic authentication credentials in the global proxy configuration on the iPads (i.e. one user name and password for all the devices - not good for seeing who's doing what but at least it would solve the problems several users are encountering with the captive web portal).
I hope I've explained my situation clearly enough. If anyone knows how if I can accomplish proxy authentication without the captive web portal I'd be grateful to hear from you.