By default, how does 3CX handle audio for extensions registered over multiple site-to-site VPNs?

3CX has a specific approach to managing audio when dealing with extensions that are registered over multiple site-to-site VPNs. By default, 3CX blocks audio between different subnets. This is mainly due to the way that audio streams are typically routed in VoIP systems, which can involve complex network configurations and considerations around NAT (Network Address Translation) traversal, as well as ensuring high-quality VoIP connections.

The reasoning behind blocking audio between different subnets is to avoid issues that may arise from misconfigured routers or firewalls between these separate networks. Incorrect configurations can lead to dropped calls or poor audio quality, which is detrimental to user experience. Therefore, by maintaining a controlled environment where audio does not cross subnets by default, 3CX prioritizes stability and reliability for calls, particularly in scenarios where interfaces between different networks may not allow for seamless audio pass-through.

This approach encourages network administrators to carefully manage their VoIP deployments and, when necessary, configure proper routing rules or use alternative solutions for scenarios requiring inter-subnet audio communication.