Configuring Fortigate Firewall for VentureTel service
There are issues with the NAT configuration on Fortigate Firewalls, while the Firewall is supported, users with these devices will likely run into the following issues using a phone behind a Fortigate:
Dropped calls
- One way or no way audio
- Potential device registration issues
- Duplicate SIP Ports and port shuffling
To mitigate some of these issues, Strict Register should be disabled to stop all phones from using a pinhole through port 65476 (external) and 5060 (internal).
Delete SIP Firewall
Access the CLI cosole in the device GUI bu clicking >_ near the upper right hand corner

In the Command Line Interface (CLI) run the following commands:
- config system session-helper
- show

- Notice that edit 13 contains SIP.
Enter the following commands:
Disable SIP Helper
In the Command Line Interface (CLI) run the following commands:
- config system settings
- set default-voip-alg-mode kernel-helper-based
- set sip-helper disable
- set sip-nat-trace disable
- end

Reboot the router using the web GUI under Status, or in the CLI with the following command:
- In the web GUI, go to System > Feature Select > Additional Features.

- Toggle Traffic Shaping and VoIP on.
- Click Apply.
Disable Strict Register
Strict Register forces VoIP devices through a pinhole at port 65476 and will cause duplicate porting to occur.
To disable this setting run the following command in the Command Line Interface (CLI):
- config voip profile
- edit "Profile Name"
- config sip
- set strict-register disable
- end

Note: The VoIP profile name can be found under Security Profile -> VoIP. Please note if these settings do not persist through a reboot a factory reset or other troubleshooting steps may be needed on the Fortigate itself with Fortigate support.
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