Is it possible to build an iOS app with the purpose of content filtering? I'll give an example. This app would block access to example.com, therefore if I were on the Safari or any iOS compatible browser, if I were to try to navigate to example.com access would be blocked. The same would happen if I were on let's say Instagram and it attempted to make an outbound api call to example.com, that too would fail. Is this device wide content filtering possible on the iOS platform?
Furthermore would you be able to implement redirect logic. As in the user tries to visit example.com but it is redirected to google.com?
Is it possible to build an iOS app with the purpose of content filtering?
Yes, but with significant deployment limitations. See the discussion of content filter providers in TN3134 Network Extension provider deployment.
Furthermore would you be able to implement redirect logic.
Not with a content filter. It’s only able to see and block traffic; it’s not able to modify it.
On macOS you can do this using a transparent proxy provider. That’s not supported in iOS.
The nearest equivalent is an app proxy provider. It has significant deployment limitations as well. Again, TN3134 has the details.
Due to these deployment limitations folks often try to twist a packet tunnel provider into performing this task. That’s not something that DTS supports, as explained in TN3120 Expected use cases for Network Extension packet tunnel providers.
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
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