Step 1: Create a “Static NAT (SNAT)”
First, the Static NAT must be configured in order to forward the incoming traffic from the Static
Public IP, to the local IP of the PBX:
- Navigate under Firebox® UI > Firewall > SNAT and click “Add”
- In this example the name “VOICEHOST_SNAT” is given to the SNAT Policy.
- Select Static NAT.
- Under SNAT Members click “Add”
- Select the “External Static IP” under the drop down menu. In this example the external IP of the device is 192.168.3.5 which should be used to NAT inbound traffic to the PBX.
- Enter the Internal/Private IP address of the PBX and click “ OK ” (in this example the internal/private IP of PBX is 192.168.4.4).
- Click “Save” and the SNAT Policy is now active.
Step 2: Create Firewall Policy
After setting up the static NAT, a Firewall Policy must be configured:
- Navigate under Firebox® > Firewall > Firewall Policies and click “Add Policy”
- In this example the name “VOICEHOST_Services” is given to the Policy Name.
- As a “Policy Type” select “Custom” and click “Add. ”
- In this example the name “VOICEHOST_Ports” is given to the “Policy Template”
- Use the “Add” button below the “ Protocols ” to add a custom list of ports which shall be allowed to connect to the PBX. (All ports and port ranges which needs to be added into this list can be found here: https://www.voicehost.co.uk/help/sip-trunk-general-settings-and-pbx-compatibility)
- “Single Port” or “Port Range” can be selected. When all ports are set, click “Save”
- Remove the “From” and “To” objects.
- Under “From” click “Add”
- Under the drop down menu select “Any External” and “OK”
- Under “To” click “Add”
- Under the drop down menu select “Static NAT”
- The SNAT created previously, will be listed (in this example “ VOICEHOST_SNAT”). Select the SNAT and “OK”
- The Firewall policy should look like the screenshot below:
In this example, “Any External” is used, therefore any host can establish a connection on the public IP Address of the PBX. In case the source of the incoming traffic must be limited you can create a group of allowed IPs to be allowed under “From.”