Does anyone have any good ideas of how to stop porn access on a smartphone? I have a Nexus 4 running lollipop. I've downloaded and use NetNanny which is a good filtering app, but it can be bypassed, so I've also installed AppLock by Domobile, which prevents access to other apps or the settings and to download new apps. This has worked fairly well, but there are two problems. First, is the new multiple users option on the phone and the second is the ability to restart the phone in safe mode. Does anyone know of any settings or apps that can prevent the ability to switch to a guest user or to restart the phone in safe mode?