How to Install Asterisk VoIP Server on Ubuntu 20.04

If you are planning to set up a VoIP Server or a Linux-based system, it is almost impossible not to have heard of Asterisk, Asterisk is the heart of many enterprise systems, call centers, and even large telecom projects. The first thing that many people encounter is that: Asterisk does not have an official repository ready for Ubuntu, and this makes its installation seem intimidating at first glance, the good news is that if you follow the steps correctly and in order, installing Asterisk on Ubuntu 20.04 is quite manageable and logical.

What should we know before starting the Asterisk installation?

1. Asterisk must be compiled from source
2. Dependencies must be installed first
3. Some libraries, like DAHDI and LibPRI, play a key role
4. It is very important not to rush and be careful with the output of the commands

Installing Asterisk VoIP Server on Ubuntu

Step 1: Update the system and install dependencies

The first step is always simple but important:

We update the system so that we don’t run into problems with old versions of packages.

sudo apt update

After that, we install the packages that are required to compile Asterisk:

sudo apt install wget build-essential git autoconf subversion pkg-config libtool -y

Practical tip: If a package doesn’t install or gives an error here, don’t continue. Most of the subsequent problems start exactly from this step.

Step 2: Compile and install DAHDI and LibPRI

Asterisk needs these two libraries to communicate with analog, digital, and ISDN phones.

Installing DAHDI

DAHDI consists of two parts:

1. dahdi-linux
2. dahdi-tools

First, we get the dahdi-linux source:

sudo git clone -b next git://git.asterisk.org/dahdi/linux dahdi-linux
cd dahdi-linux
sudo make
sudo make install
cd ..

Now it’s Dahdi-Tools’ turn:

sudo git clone -b next git://git.asterisk.org/dahdi/tools dahdi-tools
cd dahdi-tools
sudo autoreconf -i
sudo ./configure
sudo make install
sudo make install-config
sudo dahdi_genconf modules
cd ..

Installing LibPRI

LibPRI is used for ISDN-based communications:

sudo git clone https://gerrit.asterisk.org/libpri libpri
cd libpri
sudo make
sudo make install

After this step, the necessary infrastructure for Asterisk is ready.

Step 3: Get the Asterisk Source

In this tutorial, we will be using Asterisk version 18 (LTS).

sudo git clone -b 18 https://gerrit.asterisk.org/asterisk asterisk-18
cd asterisk-18

This step may take a while, especially on slow servers.

Step 4: Get MP3 Source and Asterisk dependencies

To support MP3 format:

sudo contrib/scripts/get_mp3_source.sh

Then install Asterisk-specific dependencies:

sudo contrib/scripts/install_prereq install

At this point, you may be asked for the Area Code, enter the number for your area.

Step 5: Configure and compile Asterisk

First initial configuration:

sudo ./configure

If everything is correct, you will see the Asterisk ASCII logo, Now the module selection menu:

sudo make menuselect

Practical suggestion: If you need MP3, be sure to enable the format_mp3 module.

Start compiling:

sudo make -j2

After the compilation is complete, the final installation:

sudo make install
sudo make samples
sudo make basic-pbx
sudo make config
sudo ldconfig

Step 6: Create and configure the Asterisk user

For security reasons, Asterisk should not be run as the root user.

sudo adduser --system --group --no-create-home --gecos "Asterisk PBX" asterisk

Edit the default settings:

bash
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sudo nano /etc/default/asterisk

Enable these two lines:

ini
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AST_USER="asterisk"
AST_GROUP="asterisk"

Add permissions and change file ownership:

bash
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sudo usermod -a -G dialout,audio asterisk
sudo chown -R asterisk: /var/{lib,log,run,spool}/asterisk /usr/lib/asterisk /etc/asterisk
sudo chmod -R 750 /var/{lib,log,run,spool}/asterisk /usr/lib/asterisk /etc/asterisk

Step 7: Run Asterisk and check its performance

sudo systemctl start asterisk
sudo systemctl enable asterisk

Log in to CLI:

bash
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sudo asterisk -vvvr

If you are logged into the CLI environment, the installation was successful

Step 8: Configure Firewall for Asterisk

For SIP and RTP connections:

sudo ufw allow 5060/udp

sudo ufw allow 10000:20000/udp

My Experience with Installing Asterisk

The first time I installed Asterisk, I thought it would be a simple project, but the truth is that Asterisk is detail-oriented, so here are the mistakes I made:

1. Rushly installing dependencies
2. Ignoring compilation errors
3. Running Asterisk as root

After a few installations and messing around, I quickly realized:

1. If you follow the steps, Asterisk won’t bother you
2. You should really read the output of the commands
3. Security is very important

For me, Asterisk is now one of the most stable services I run on the server, and I also share my other experiences on our website, check out for more.

Conclusion

Installing Asterisk on Ubuntu 20.04 may seem complicated at first sight, but the truth is that if you follow the steps patiently and in order, everything will be quite manageable for you. Most of the challenges come not from Asterisk itself, but from rushing and not paying attention to the output of commands, Asterisk is not a simple tool, it is a complete communications platform that gives you a lot of power and this high power makes its installation and setup require more precision, When you successfully complete this step, you will have built the foundation for a stable and scalable phone system, If you have followed this tutorial step by step, you now have a working Asterisk on the server and can safely move on to more advanced settings such as creating extensions, routing calls, or connecting to FreePBX, from here on, Asterisk is no longer a challenge, It’s a tool you can count on.