> For the complete documentation index, see [llms.txt](https://cookbook.denovolab.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cookbook.denovolab.com/configure-a-new-class-4-instance/setup-sip-switch.md).

# Setup SIP Switch

Each UI can connect to as many SIP Switch as you want.  These SIP Switches can be running in different servers also.  Each Class 4 switch has a telnet port and this telnet port enable the UI to communicate with it. 

Here is how you need to do to setup the SIP Switch:

![Click on VoIP Gateway on right side](/files/-MdtWTuvXjLYuSEe626Z)

 In the VoIP Gateway page, you can specify the telnet IP and port to access to the dnl\_softswitch instance:

![](/files/-MdtWnSlXLj0kuFC8m_W)

Each dnlsoftswitch instance can listen to multiple SIP IP:port.  You can click on + to add as many SIP IP:port combination as you need. 

![](/files/-MdtX0KKeJWX8AKrxfUH)

After you modify the VoIP gateway, you will need to restart dnl\_softswitch instance in order for the change to take place. 

You can use the following command to check if the SIP port is live or not:

```
[root@ns505183 ~]# netstat -anp |grep 5060
udp        0      0 198.27.82.144:5060      0.0.0.0:*                           27257/dnl_softswitc 
[root@ns505183 ~]# netstat -anp |grep 5080
udp        0      0 198.27.82.144:5080      0.0.0.0:*                           27257/dnl_softswitc 
[root@ns505183 ~]# 
```