How to Start a Voice over IP (VoIP) Server: Operation Guide (Asterisk Example)

Voice over IP (VoIP) technology allows you to make voice calls using a broadband internet connection instead of a regular phone line. Setting up a VoIP server can seem daunting, but it becomes manageable when broken down into clear steps. In this guide, we will walk you through the process of starting a VoIP server using Asterisk, an open-source communications server.

Step 1: Choose Your VoIP Server Software

Asterisk is a popular choice for building VoIP systems due to its flexibility and wide range of features. Before proceeding, ensure you have the necessary hardware and network infrastructure to support your VoIP server.

Step 2: Prepare Your Hardware

Server Hardware

  • Server: A reliable server with sufficient CPU, RAM, and storage to handle the expected call volume.
  • Network : A robust network setup with sufficient bandwidth and low latency.

VoIP Devices

  • VoIP Phones or Softphones: Devices or applications that will be used by clients to make and receive calls.

Step 3: Install the Operating System

Choose an OS

Asterisk can run on various operating systems, but it is commonly deployed on Linux distributions such as CentOS, Ubuntu, or Debian. For this guide, we will use Ubuntu.

Install the OS

Perform a clean installation of your chosen Linux distribution on your server hardware.

Step 4: Install VoIP Server Software (Asterisk)

Update the System

First, ensure your system is up to date:
sudo apt update && sudo apt upgrade

Install Dependencies

Install the necessary dependencies for Asterisk:
sudo apt install build-essential libxml2-dev libsqlite3-dev uuid-dev

Download and Install Asterisk

1. Download Asterisk:
cd /usr/src
sudo wget
2. Extract the Tarball:
sudo tar -zxvf asterisk-18-current.tar.gz
cd asterisk-18.*
3. Compile and Install Asterisk:
sudo ./configure
sudo make
sudo make install
sudo make samples
sudo make config
sudo ldconfig

Start Asterisk

Start the Asterisk service and enable it to run on boot:
sudo systemctl start asterisk
sudo systemctl enable asterisk

Step 5: Configure VoIP Server

Basic Configuration

SIP Configuration
Edit the sip.conf file to define SIP settings:
sudo nano /etc/asterisk/sip.conf
Add the following example configuration:


Extensions Configuration

Edit the extensions.conf file to define call routing and dial plans:
sudo nano /etc/asterisk/extensions.conf
Add the following example configuration:
exten => 1001,1,Dial(SIP/1001)
exten => 1002,1,Dial(SIP/1002)

User Accounts

Create user accounts for each VoIP phone or softphone client by editing the 'sip.conf' and 'extensions.conf' files.

Step 6: Connect VoIP Phones


Download and install softphone applications like Zoiper or Linphone on client devices.


Use the account details created in 'sip.conf' to set up each client device.

Step 7: Test the VoIP Server

Make Test Calls

Ensure that clients can register with the server and make internal and external calls.

Check Logs

Monitor server logs for errors and resolve any issues.

Step 8: Secure Your VoIP Server


Configure your firewall to allow VoIP traffic (e.g., port 5060 for SIP).


Install Fail2Ban to protect against brute-force attacks.


Enable SRTP (Secure Real-time Transport Protocol) for encrypting voice traffic.

Step 9: Monitor and Maintain

Monitoring Tools

Use tools like Nagios or Zabbix to monitor server performance and call quality.

Regular Updates

Keep the OS and VoIP software updated with the latest security patches.

Optional: Advanced Features


Configure voicemail settings for users.


Set up Interactive Voice Response menus.

Call Recording

Enable call recording for quality control or legal purposes.

Conclusion: Voice over IP Server

By following these steps, you can set up a fully functional VoIP server using Asterisk, capable of handling voice communication over IP networks. Adjust configurations based on specific requirements and scale your setup as needed.

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