Is it necessary to define both an external and internal FQDN for 3CX to function properly in a NATed environment?

In a NATed environment, it is indeed necessary to define both an external and an internal Fully Qualified Domain Name (FQDN) for 3CX to function correctly. The external FQDN is used by remote users and devices to connect to the 3CX server from outside the local network, ensuring that authentication and proper routing of SIP and media traffic can occur over the internet.

On the other hand, the internal FQDN plays a crucial role for devices and users within the local network. It allows these internal clients to access the server reliably without unnecessary routing through the external address, which can lead to issues such as latency and complications in NAT traversal. Having both FQDNs configured allows for seamless connectivity regardless of whether the clients are accessing the system from within the local network or remotely.

This dual FQDN configuration is integral for maintaining proper communication, avoiding common pitfalls associated with NAT environments, and ensuring that both internal and external users have a consistent and reliable connection to the 3CX system.