This post is part of the Local Network Privacy FAQ.
On a small fraction of devices my app fails to present the local network privacy alert. What’s going on?
I most commonly see this in apps with code that specifically targets the Wi-Fi interface. If that code fails, the app might end up targeting the wrong interface. If that interface is not subject to local network privacy, the system never presents the local network privacy alert.
IMPORTANT A common cause of this failure is the assumption that en0 is the iPhone’s Wi-Fi interface. While that’s true on most devices, this is not a valid assumption. BSD interface names are not considered API on Apple platforms. Code that makes that assumption will fail in hard-to-reproduce circumstances.
If you encounter a problem like this, check whether your code has a hard-coded en0. If it does, see Extra-ordinary Networking for ideas about how to fix it.
