iPhone IOS 13.3 issue - 2 iPhones cannot talk

[Kane Wong]

Hi;
This is what I found in my 3CX network, my 3CX server is on subnet 192.168.1.x and my iPhone users is on a Wifi subnet 172.16.1.x, the communication between the wifi subnet to 3CX server is through interVLAN routing.

The problem is that two iPhone cannot talk in this setup but iPhone and Android phone can talk, no problem. Android phone and the iPhone is using the same wifi subnet.

My network team conclude that the 3CX app for Android know how to use the Internal IP and the External IP, we assume that because the wifi subnet and the 3CX server subnet are not the same, the 3CX app will try to use External IP, or Internal IP depends on which one can be communicated with the 3CX server.

But the iPhone 3CX app cannot switch from External IP to Internal IP therefore even though, I can ring from iPhone 1 to iPhone 2 but no voice signal.

Anyone has the same issue?

 

[Vali_3CX]

I guess is the same issue you reported here and I just answered:
https://www.3cx.com/community/threa...ile-the-signal-bar-on-3cx-app-is-white.70979/

However, be careful with the test case you've mentioned here, you can be easily fooled:
- first of all, both Android and iPhone should be configured with same account and have the same settings (mainly tunnel and audio codecs) - in order to be considered "identical". If extensions are different, apart from this there is the Management Console extension' "PBX delivers audio" settings which has a major impact.
- then, there are two different devices, with two different local IPs - one can be blacklisted, the other one no (OK, it's not the case here)
- one device may have a single known WiFi it joins automatically, while the other may have many so it could switches between them or 3G without you being immediately aware of
- one device may have manually added proper DNS, while other may not.

Such kind of details, they can be easily missed out in test cases.