How to Configure a STUN Server in 3CX Phone System for Testing

In this post we show you how to enable STUN in order to test 3CX Phone System using a dynamic public IP address. By default, 3CX Phone System assumes that you have a static public IP address and disables the STUN server option. A static public IP is needed in order for VoIP providers, remote extensions and WebRTC calls to work. Note that use of a dynamic IP address is only suited for testing 3CX Phone System. It is not recommended for a production system.

Specifying STUN Server

stun server

  1. In the 3CX Management Console, go to “Settings” > “Network” node. Click on the “STUN server” tab.
  2. Uncheck the “Turn off STUN requests” checkbox.
  3. In the “Primary STUN server” entry field, specify the STUN server suggested by your provider. Specify the port if needed (default: 3478).
  4. You can specify an alternate backup server, or leave the “” as the backup STUN server. This address will be used if the primary STUN server cannot be reached. Click “OK” to exit and save the settings.