The Project

This repository should contain the basis to help you build a simple, reliable and flexible VoIP / SIP intercom system for residential or commercial buildings using free software only. On the market, you may find companies naming this solution as "smart doorbell".

The system is composed of:

• SIP server, the "brain" on the intercom system.
• Various SIP clients connecting from the local network or the internet.
• The doorbell device. It's is a "fancy" SIP client able to control an electric door lock.

Here is an example of how the devices can be connected:

The SIP protocol and various device types available on the market allow us to build a system to meet our needs. We can use doorbell devices like the Niteray Q520 or Fanvil i30 equipped with a built-in camera and a dial pad. Other options would be the Akuvox R26 or Algo 8201 door phones, equipped with a single dial button. There are several makes and models out there, pick the hardware that works best for you, the functionality and details we can tailor on the "brain".

We set up a SIP server running Asterisk on a Docker Container. Asterisk is lightweight so we don't need lots of processing power, we can host the it on nearly any computer nowadays, including old laptops and Raspberry Pi models 3, 4 or similar.

Another way to architect the solution would be hosting the SIP server on a virtual server far away from your local network. This project can help you if this is what you are looking into but deeper adjustments to the configuration templates would be required.

Table of Contents

• conf
  • This directory contains Asterisk configuration files. The most relevant files are:
    • The extensions.conf file is the dialplan, here we configure the dial groups and call route logic.
    • The pjsip.conf contains critical resource configuration like SIP users/clients credentials and other network configuration. Set local_net, external_media_address and external_signaling_address as required. Clients configuration start on line 51.
• docker
  • Our Container image recipe is the Dockerfile and the docker-compose.yml help us configure our environment. Some settings you may want to update are:
    • Asterisk version
    • Time Zone
    • Dockerfile path
    • Volumes path
• logs
  • No relevant files here yet. We configure our Container and scripts to create logs files under this directory.
• scripts
  • Here we have a few helper scripts to run our SIP server reliably:
    • The crontab_bkp file is an example/suggested crontab file.
    • The disk_monitor.sh script helps monitor storage space usage by sending email notifications using msmtp.
    • The logs_monitor.sh script helps to keep the log files size under control reducing unnecessary storage space usage.
    • The ip_monitor.sh is useful for dynamic IP users. This script monitors a given hostname records and updates it as needed on the duckdns.org DDNS service.
    • The reference_IP.txt file is a control file used by the sip_monitor.sh script.
    • The sip_monitor.sh script monitors the reference_IP.txt and restarts the SIP server Container as needed due to an IP address change.
    • The scripts.log file is where the scripts store actions/events/debug information.
• sounds
  • Directory where we store audio/media to be used by Asterisk, our SIP server.

Installation process

The steps are the same on any Linux distro but the commands would only work on a debian-like distros.

1. Install the Operating system on your hardware. Get OpenSSH server ready so you can access it remotely.
2. Connect to the server

   ssh user@serverIP
   sudo su
   

3. Create the directory where the project files should sit in

   mkdir -p /home/data/
   

4. Install required software

   apt install git msmtp docker.io docker-compose
   

5. Clone this repository

   git clone https://gitlab.com/andre.rodovalho/sip-doorbell-brain.git /home/data2/sip-doorbell-brain/
   

6. Copy the required files and directories

   cp -r /home/data2/sip-doorbell-brain/{conf,docker,logs,scripts,sounds} /home/data/
   

7. Build the SIP server Container

   docker-compose -f /home/data/docker/docker-compose.yml build
   

8. Configure an SMTP server for msmtp

   nano ~/.msmtprc # configure an SMTP server: 
   

9. Adjust the management scripts as required

   nano /home/data/scripts/disk_monitor.sh	# configure DESTINATION email address
   nano /home/data/scripts/ip_monitor.sh	# configure DOMAIN and TOKEN
   nano /home/data/scripts/sip_monitor.sh	# configure DOMAIN
   chmod 744 /home/data/scripts/*.sh	# make all scripts executable
   

10. Configure your SIP server

    nano /home/data/conf/extensions.conf	# configure extensions
    nano /home/data/conf/pjsip.conf		# configure SIP clients credentials
    

11. Start up the SIP server

    docker-compose -f /home/data/docker/docker-compose.yml up -d
    

12. Configure a SIP client
13. Try connecting to the server
14. Troubleshooting connectivity issues (if needed)

    docker exec -it sipserver asterisk -rvvv
    

15. Configure required scheduled jobs

    crontab -e
    

Additional (recommended) steps

1. Install fail2ban

   apt install fail2ban
   

2. Configure a custom jail to stop brute-force attacks

   nano /etc/fail2ban/jail.local
   

   • The file contents can look like the below:

   [DEFAULT]
   ignoreip = 127.0.0.0/8 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
   
   [asterisk]
   enabled  = true
   filter = asterisk
   port     = 5060
   action   = iptables-allports[name=asterisk, protocol=all]
   logpath  = /home/data/logs/messages
   maxretry = 10
   findtime = 1800
   bantime = 3d
   #backend = auto
   
   [recidive]
   enabled  = true
   maxretry = 3
   logpath  = /var/log/fail2ban.log
   #banaction = %(banaction_allports)s
   action   = iptables-allports[name=recidive, protocol=all]
   bantime  = 1m
   findtime = 3d
   

3. Restart the service to apply changes

   systemctl restart fail2ban
   

4. Enable the service

   systemctl enable fail2ban
   

Note

We won't cover the steps to configure your modem/router/NAT settings here. You would need to configure your equipment to forward ports 5060 and the 10000-20000 range to your server in order to expose the SIP server to the public. Check your equipment user's manual for instructions.

Disclaimer

Copyright (C) 2021-present Andre Campos Rodovalho.

This program is free software: you can redistribute it and/or modify it under the terms of the MIT License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; please check out the LICENSE file for more information.

ASTERISK is a registered trademark of Sangoma Technologies Corp.

Docker is a registered trademark of Docker, Inc. in the United States and/or other countries. Docker, Inc.

SVG icons used here came from svgrepo.com

All trademarks, logos and brand names are the property of their respective owners. All company, product and service names used in this software are for identification purposes only. Use of these names, trademarks and brands does not imply endorsement.