What I Built

I set up a home VoIP system using Asterisk as the server and Twinkle as the softphone client. Everything here runs on Ubuntu — same network, two extensions, calls between machines.

How VoIP Works

VoIP sends your voice as data over the internet instead of through a phone line. Cheaper than landlines, especially for long-distance — that’s why I tried it.

Asterisk as the Server

Asterisk is the PBX — it handles call routing between extensions. I compiled it from source on Ubuntu.

Installing Asterisk

Here’s what I ran:

sudo apt update && sudo apt upgrade -y

Step 2: Install Essential Dependencies

Asterisk requires a bunch of dependencies to function properly. Install them all in one go:

sudo apt install -y gnupg2 software-properties-common git curl wget \
    libnewt-dev libssl-dev libncurses5-dev autoconf subversion \
    libsqlite3-dev build-essential libjansson-dev libxml2-dev pkg-config \
    libtool uuid-dev

Step 3: Install DAHDI and LibPRI (For Extra Features)

If you want better telephony support, install DAHDI and LibPRI:

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

cd /usr/src/
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 /usr/src/
sudo git clone https://gerrit.asterisk.org/libpri libpri && \
cd libpri && sudo make && sudo make install

Step 4: Install Asterisk

Now for the main event—installing Asterisk itself:

cd /usr/src/
sudo git clone -b 18 https://gerrit.asterisk.org/asterisk asterisk-18 && \
cd asterisk-18/ && sudo contrib/scripts/get_mp3_source.sh && \
sudo contrib/scripts/install_prereq install && sudo ./configure && \
sudo make menuselect && sudo make -j2 && \
sudo make install && sudo make samples && sudo make config && sudo ldconfig

Step 5: Create Asterisk User

It’s best to run Asterisk under a dedicated user:

sudo adduser --system --group --home /var/lib/asterisk --no-create-home --gecos "Asterisk PBX" asterisk
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 6: Configure Asterisk

extensions.conf

Edit the extensions.conf file:

sudo nano /etc/asterisk/extensions.conf

Add the following:

[from-internal]
exten = 100,1,Answer()
same = n,Wait(1)
same = n,Playback(hello-world)
same = n,Hangup()

sip.conf

Edit the sip.conf file:

sudo nano /etc/asterisk/sip.conf

Add these configurations:

[general]
context=default

[6001]
type=friend
context=from-internal
host=dynamic
secret=temp123
disallow=all
allow=ulaw

[6002]
type=friend
context=from-internal
host=dynamic
secret=temp123
disallow=all
allow=ulaw

Step 7: Configure Firewall for Asterisk

Don’t forget to allow VoIP traffic through the firewall:

sudo ufw allow 5060/udp
sudo ufw allow 10000:20000/udp

Step 8: Start Asterisk

Everything is set! Start Asterisk and check its status:

sudo systemctl start asterisk
sudo asterisk -vvvr

Installing Twinkle (Softphone)

To test our Asterisk setup, install the Twinkle softphone:

sudo apt install -y twinkle

Configuring Twinkle

  1. Open Twinkle and select “Wizard”.
  2. Enter a profile name.
  3. Fill out the configuration form (use temp123 as the password, as set in sip.conf).
  4. Save and confirm the settings.
  5. Use the main menu to place calls.

For testing, install Twinkle on a second system and configure it with 6002 instead of 6001. Ensure both clients are on the same network.

That’s it! You now have a working VoIP setup using Asterisk and Twinkle.