Remote Devices Using Stun; Figure 9: Outbound Proxy Setting - Grandstream Networks 3CX Configuration Manual

7. Click on Save and Apply to register the extension with 3CX Phone System as tunneled via 3CX
SBC.

Remote Devices using STUN

To configure a remote Grandstream device using STUN, follow below instructions:
Note: We will use GXP2135 as example. Same configuration applies to other models.
1. Take note of the SIP extension credentials from 3CX Phone System to be configured on the device.
2. Log in to the phone and go to Account  General Settings.
3. Make sure to set Account Active to "Yes".
4. Fill the information related to SIP extension created on the 3CX Phone System.
5. In SIP Server field, enter the public IP/FQDN of 3CX Phone System ("testgs.3cx.eu" in this
example), and click on Save.
Configuring Grandstream Devices with 3CX Phone System

Figure 9: Outbound Proxy setting

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