For sysprefs like: RestrictedPageLocalIP we check the REMOTE_ADDR to get the IP, for setups behind a proxy we have seen issues as the IP is not matching the users IP.
We should have a support for checking X_FORWARDED_FOR in order to check the IP of the end user
I just wanted to chime in that this effects us, as we'd like to offer limited access to media via the Restricted Page feature without forcing a sign-in from on campus but are hosted behind a proxy by ByWater.
I would also like to add that we would be interested in a solution to this issue as well. It is preventing us from providing the best customer service we can as a library.
*** This bug has been marked as a duplicate of bug 23068 ***