Configuring a Singtel SIP Trunk

Step 1: System Preparation

Network Topology

In order to use a SingTel SIP Trunk with 3CX, the 3CX Server needs to have a second network card which will only be used for traffic from and to the SingTel servers. The network topology should look similar to the following:

NIC 1 should connect to the main LAN through which the 3CX Server will have access to the internet and will also be the LAN on which Extensions are connected to.

NIC 2 will only cater for traffic from/to the SingTel servers.

3CX Server NIC Setup

For NIC 1, apply the necessary network settings required by your network.

For NIC 2, you must manually configure the SingTel WAN IP address that has be given to you and as per the instruction by SingTel, e.g.:

Important! NIC 2 must not have a Default Gateway configured and the DNS servers must be blank.

Adding Static Routes

Next you must add a static route so that the traffic from the 3CX server towards the SingTel servers is routed out through the correct Gateway. To do this on a Windows OS, you would open a command prompt using the “Run as Administrator” option, then run the following command:

        route -p add 202.163.63.0 mask 255.255.255.0 METRIC 1 [Gateway IP given by Provider]

e.g.:

        route -p add 202.163.63.0 mask 255.255.255.0 METRIC 1 117.58.169.189

The Gateway IP that you need to configure should be given to you by SingTel.

Step 2: Collecting 3CX Configuration Settings

In order to configure SingTel with 3CX, you should first make sure you have the following information available which must be provided to you by your SingTel representative:

• Your DID numbers
• The SingTel SIP Server IP address
• Your SingTel WAN IP Address (also used in section 3CX Server NIC Setup)

With the above information you can proceed to the next section which explains how you use this information to configure the Trunk in 3CX.

Step 3: Configuring your SIP Trunk with 3CX

1. Go to the 3CX Web client and follow the guide on how to configure a SIP trunk.
2. Not compatible with hosted by 3CX.

Adding the Trunk

In the “General” tab fill in the SingTel SIP Server IP given to you by the Provider in the “Registrar” field:

Next, go to the “Options” tab and in the “Advanced” section, fill in the SingTel WAN IP you have been given.

Once you have done the above, press OK and your Trunk will now be configured.

About Singtel

The Singtel Group is Asia's leading communications group, with their headquarters in Singapore. They provide a diverse range of services including fixed, mobile, data, internet, TV, infocomms technology (ICT)  and digital solutions.

Last Updated

This document was last updated on 7 July 2023

https://www.3cx.com/docs/sip-trunk/singtel-asia/