If you are using a VoIP provider, you will need to have a firewall that supports and is configured to use static port mapping. Static port mapping is required for RTP, the protocol that carries audio, to be able to function correctly. RTP and Symmetric NAT VoIP applications that use the RTP protocol to send and receive audio and video streams, tend to have problems behind a fir [...]
By Nick Galea|May 3rd, 2009|Comments Off on Why Does 3CX Require Static Port Mappings (Full Cone NAT)?