How to tell if iMessage is going over wifi or cellular?

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Level 1

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How to tell if iMessage is going over wifi or cellular?

Unique situation allowed me to see something odd. My household internet connection is toast. Wifi is there, but no internet. My phone was connected to wifi and I could still send iMessage. I thought, how could this be? I have no internet on my wifi connection? Then I turned off cellular data and the iMessage stopped working. So this leads me to believe it is using cellular even when connected to wifi. Is this true? In that case, seems like you could be connected to wifi and if you were in a spotty area on your wifi it will use LTE as backup? So you could be using your cellular data without knowing it? I just thought it was interesting. Thanks!

Posted on Apr 17, 2019 11:58 AM

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Answer 1

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Michael Black

Level 10

81,257 points

Apr 17, 2019 1:11 PM in response to jrsauce

But you have a cellular signal and a cellular data plan. Since your WiFi is not able to connect to the internet, iMessage will happily use cellular data to connect to the internet. The iMessage service just needs an internet connection but it can be WiFi or cellular data. The messaging app will access the internet anyway the device is configured to allow for.

So if your WiFi is out you would need to also disable cellular data to stop iMessages from going out or coming into your device.

Wifi assist is in the cellular data settings and applies to those apps listed there - but you’ll note that the messaging app is not one of those that you can disable it for. I assume that’s because the single iOS messaging app handles iMessage as well as both SMS and MMS texts. WhatsApp is in my list of third party apps that I can disable WiFi assist for, but not the built in iOS messaging app.

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