: Technical descriptions from the Google Play Store for InternetGuard explain that it uses the Android VpnService API to create a local "tunnel." All data traffic is routed through this local proxy to be filtered without needing "root" access .
: This IEEE conference paper analyzes whether mobile firewalls actually block traffic as expected. It notes that many firewalls do not block 100% of network traffic even when configured to do so .
Installing a "Mod Full" version of an app typically means using a version altered by a third party to unlock premium features for free. Research indicates this is a high-risk activity.