iosios14

What triggers the "would like to find and connect to devices on your local network" permission notification on iOS 14?

What actual method calls, excluding Bonjour, triggers the "would like to find and connect to devices on your local network" permission notification on iOS 14?

This is the screen shot from the WWDC session on this new permission. Which is only somewhat helpful as an overview. I'm more interested in figuring out what all method calls trigger this.

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Solution

  • Apple (Eskimo on the Dev Forums) released a FAQ providing more details around this alert: https://developer.apple.com/forums/thread/663858

    Particularly, providing more info as to what triggers this alert is FAQ-2: https://developer.apple.com/forums/thread/663874

    What operations require local network access?

    The general rule is that outgoing traffic to a local network address requires that the user grant your app local network access. Common scenarios include:

    • Making an outgoing TCP connection — yes
    • Listening for and accepting incoming TCP connections — no
    • Sending a UDP unicast — yes
    • Sending a UDP multicast — yes
    • Sending a UDP broadcast — yes
    • Receiving an incoming UDP unicast — no
    • Receiving an incoming UDP multicast — yes
    • Receiving an incoming UDP broadcast — yes

    These TCP and UDP checks are done at the lowest levels of the system and thus apply to all networking APIs. This includes Network framework, BSD Sockets, NSStream, NSURLSession and WKWebView, and any other protocols that you layer on top of those.

    IMPORTANT Receiving an incoming UDP multicast or broadcast does not currently require local network access but, because we hope to change that in a future update, our advice right now is that you write your code as if did (r. 69792887, 70017649).

    Resolving link-local DNS names (those ending with local, per RFC 6762) requires local network access. Again, this check applies to a wide variety of APIs including <dns_sd.h>, <net_db.h>, Network framework, NSStream, and NSURLSession.

    Finally, all Bonjour operations require local network access:

    • Registering a service with Bonjour — yes
    • Browsing for Bonjour services — yes
    • Resolving a Bonjour service — yes

    Again, these checks apply to all APIs that use Bonjour, including <dns_sd.h>, Network framework, NSNetService, and Multipeer Connectivity.

    Note You must declare the Bonjour service types you use in your Info.plist. See How do I map my Multipeer Connectivity service type to an entry in the Bonjour services property? for details.

    Bonjour-based services where you don’t see any details of the network do not require local network access. These include:

    • AirPlay — no
    • Printing via UIKit — no