Issues sending UDP data from an UE4 iOS app

Development Programming & Scripting Multiplayer & Networking
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So… i have this system sending information between different ue4 clients over udp. And it all works fine, except on iOS. I can send data -TO- an ios device over udp and that works fine. But sending data -FROM- the device… that doesnt seem to work. The packets doesnt seem to get sent. And it works fine from all other places.

I can confirm running the setup from pc to pc it all works fine, and even TCP sockets from ios also works like normal.
And other UDP applications from the same device can send with no issues…

I cant really find a reason why it doesnt work…
Are there issues sending UDP data from an UE4 application on iOS? Any way to get this to work?

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I have a similar problem for iOS 15 / iPad and would love to know if you solved this.

I noticed there’s no prompt in iOS to ask about local network connection either, as there is with other apps that use UDP messaging. I’m sending UDP messages to a PC on the local network via the OSC plugin. Works fine between PCs, doesn’t work from iOS.

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So I’ve made some more progress here… it seems there’s a few steps.

This is the first time I’ve finally needed to enroll in the Apple Developer programer, and not just used the autosign feature in Unreal.

  1. Contact Apple to request permission to use the Multicast entitlement.
  2. Add the entitlement to your plist by going to Project Settings > iOS > Additional Plist Data, or in Xcode, I’m not sure yet.

Some posts that have helped so far:

https://forum.unity.com/threads/ios-14-5-can-not-send-udp-broadcast.1116352/