3cx iOS (+ Android?) client - please add "url trigger" option The idea is to trigger VPN connection (company VPN), as Apple removed "always-on" support (legal issues) - only "on-demand" is working, but it that case something must trigger VPN. The way it works - DNS must provide local IP address which is not accessible directly, then VPN will be established. Easiest way to support this from an application - provide setting "attempt to access some URL before registration", for example Acrobits softphone can do that. 3CXtunnel is not really secure option as password is shared between all users, plus not really clear what kind of encryption is used.