Remote Stun; Figure 2: Remote Phone Located Behind Sbc - Grandstream Networks 3CX Configuration Manual

Remote STUN

Grandstream Devices support STUN mode in SIP Network Settings, allowing them to communicate with
3CX Phone System across the WAN.
3CX Phone System must be using a static public IP / FQDN, and the firewall should allow SIP / RTP traffic:
•
TCP port configured during installation used for the provisioning of remote extensions (in this guide,
8001 with HTTPS).
•
UDP port 5060: used for SIP traffic.
•
UDP ports 9000–9500: used for RTP traffic (audio/video).
In this network setup, we consider the following:
•
3CX Phone System FQDN is "gstest.3cx.eu".
•
Grandstream device is behind a router with dynamic IP.
Configuring Grandstream Devices with 3CX Phone System
Router
Switch
3CX Phone System
FQDN: gstest.3cx.eu
Private IP: 192.168.5.116

Figure 2: Remote Phone Located Behind SBC

Internet
Router
Switch
IP: 192.168.6.225
3CX SBC
IP: 192.168.6.31
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