Solved Android App not working outside of local network

[ZoloN]

hi Vali,

I see, thank you for explanation.

on the other hand, from network point of view, the tunnel acts as VPN tunnel encapsulating the SIP and voice packets to single TCP connection and routing them directly to the 3CX PBX host traversing thru lot of routers, NAT setups, etc... (for example, while on LTE my mobile gets a private 10.x.x.x IP which is then NATed to some shared public IP) - and the PBX should only know, where to route the responses (to tunnel instead of LAN). honestly, I don't see any reason behind to use public FQDN in the SIP INVITE packets. it's little bit confusing while analyzing the captured network traffic.
changing this to unified INVITE format (using internal FQDN/IP) could prevent some unintentional noob misconfigs...
and another reason for unifying could be: as the App connects to the PBX via tunnel even on local network, to simplify the App code - no need for location discovery and double handling of SIP protocol, which can contribute to more clean code of App and avoid possible errors in future versions

/BR
ZoloN

 

[Vali_3CX]

I'm not an expert in networking, but in my opinion the best configuration for the PBX is to have an unique FQDN for both internal/external (I think this is split DNS)

 

[ZoloN]

conclusion: after setting up the FQDNs with split DNS based on advice from Vali all is working fine.

case closed!