Setup SIP Trunk on 3CX Phone System

Configuring a VoIP Provider / SIP Trunk

Step 1: Create an Account with a VoIP Provider

First off, you need to have an account with us. Our SIP Trunks has been tested by 3CX. As 3CX includes pre-configured templates for these I.T Communications. Simply select “VoIP Providers” > “Add VoIP Provider” and select UK from the Country list. You will then see I.T Communications from the Provider drop down menu.

Step 2: Add the VoIP Provider Account in 3CX Phone System

After you have created the VoIP provider account, you will need to configure the account in 3CX Phone System. To do this:

1. In the 3CX Phone Management console menu, select “VoIP Providers” > “Add VoIP Provider”

2. The 3CX Phone System will prompt you to conduct a Firewall Test . Frequently, the internet facing firewall sitting between 3CX Phone System and the VoIP provider is not correctly configured or is not able to correctly route VoIP traffic. To check the firewall configuration, it is important to perform a firewall check using the inbuilt firewall checker.

• Click “Run Firewall Checker”. It will use the STUN server configured in “Settings” > “Network” > “STUN Server”
• Ensure that your firewall allows and correctly routes connections on Port 5060 (for SIP) and Ports 9000 – 9099 (for RTP Audio) to the PBX. If the firewall checks fail, you will not be able to reliably make and receive VoIP provider calls and you will have to edit your firewall configuration. 

After successfully completing the test, return to the VoIP Provider Wizard.

Note: I.T Communications / 3CX does not provide specific firewall configuration support.

Add VoIP Provider Account

3. Enter a friendly name for this VoIP provider account.
4. Select the Country drop down menu and select UK
5. Select your I.T Communications from the Provider drop down list.

•  Click “Next”.

6. The SIP server hostname or IP may be pre-filled. Compare these with the details that you have received from your us and check that these are indeed correct. Click “Next” to continue.
   
   
7. Now enter the SIP Trunk account details. In the External number field, enter the VoIP line number that has been assigned to you. this must start with 44 leaving the first 0 from your full number then enter the Authentication ID/username and password of your VoIP provider account. Specify the number of simultaneous calls your provider allows. Click “Next” to continue.
   
   
   
8. Specify how calls from this VoIP provider should be routed. You can specify a different route outside office hours. The routing configured here will take effect when no inbound routing rules are matched.
   
   
9. On the next page, you can optionally configure an outbound call rule, which will be used to route outbound calls through the new SIP Trunk. This is normally done by routing calls starting with a specific prefix. Enter the dialling prefix in the “Calls to numbers starting with (prefix)” text box. To make calls via this provider, precede the number to be dialled with this prefix.

DID’s and Inbound Call Identification

If your account included inbound phone numbers, you will need to specify these in the DID tab. To do this:

1. In the 3CX Management Console, select “VoIP providers” click on the VoIP provider you want to configure.
2. Click on the “DID” tab.
3. Add the DID numbers associated with your account. An Inbound Rule, which can be configured at a later stage, will be created for each number specified in this list.

You can also see the list of inbound rules by expanding the “Inbound Rules” node.

Please also add the following IP Addresses in 3CX > Settings > Security - IP Blacklist as an allowed Rule

Network Address: 212.38.169.224
Subnet Mask: 255.255.255.224
Action: Allow
Description: VoIP Network

Network Address: 212.38.183.0
Subnet Mask: 255.255.255.224
Action: Allow
Description: VoIP Network

Network Address: 78.129.164.64
Subnet Mask: 255.255.255.224
Action: Allow
Description: VoIP Network

Click OK as pictured above and do the next IP Range.

Once fully completed you should see the screen look like below.

click Apply and OK at the bottom of the screen.