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Configuring FreeSWITCH for the First Time on Alma Linux

Configuring FreeSWITCH for the First Time on Alma Linux

October 29, 2024·İbrahim Korucuoğlu
İbrahim Korucuoğlu

Introduction

Once FreeSWITCH is successfully installed on Alma Linux, the next step is configuring it to meet your specific requirements. FreeSWITCH provides a flexible and powerful platform for handling various telephony functions like voice, video, and messaging. However, to take full advantage of its capabilities, an initial setup and configuration process is crucial. This guide walks through essential configurations, including setting up SIP profiles, dialing plans, codecs, and security measures for configuring FreeSWITCH.

Prerequisites

To follow along with this guide, you should have:

    - ***FreeSWITCH is installed on Alma Linux*** following proper installation procedures.
    • Root or sudo access on the Alma Linux server.
    • Basic understanding of SIP and VoIP concepts for effective configuration.

    Step 1: Directory Structure and Configuration Files Overview

    FreeSWITCH’s configurations are stored in the /usr/local/freeswitch/conf directory, with each major area divided into distinct folders:

      - ***dialplan*** : Contains files for defining call routing rules.
      • sip_profiles : Holds configurations for SIP profiles, which manage SIP connections.
      • vars.xml : A core file defining global variables for the FreeSWITCH environment.

      Familiarizing yourself with these directories will make configuration easier and more organized.

      Step 2: Setting Global Variables

      The vars.xml file in /usr/local/freeswitch/conf is the primary configuration file for setting up global variables. Here’s how to customize it:

        - Open vars.xml with a text editor: 
           sudo nano /usr/local/freeswitch/conf/vars.xml
          - Modify key variables such as:
            - ***Domain Name*** : Set this to the server’s IP or domain name for identification purposes.
            xml <X-PRE-PROCESS cmd="set" data="domain_name=your.domain.com"/>
            • SIP Ports : You can specify custom SIP ports if desired:
              xml <X-PRE-PROCESS cmd=“set” data=“external_sip_port=5060”/> <X-PRE-PROCESS cmd=“set” data=“internal_sip_port=5061”/>

            After making these changes, save the file and restart FreeSWITCH to apply them:

            sudo systemctl restart freeswitch

            Step 3: Configuring SIP Profiles

            FreeSWITCH organizes SIP configurations in “profiles” to separate internal and external connections. The default SIP profiles are stored in /usr/local/freeswitch/conf/sip_profiles.

              - ***Internal SIP Profile*** : This profile is generally used for internal devices within the same network.
                - Open internal.xml to configure internal settings: 
                sudo nano /usr/local/freeswitch/conf/sip_profiles/internal.xml
                  - Set the bind address to the local IP, or leave it as 0.0.0.0 to allow connections on any network interface:
                  xml <param name="sip-ip" value="0.0.0.0"/>
                    - ***External SIP Profile*** : Configure this profile to handle external connections, often used for connecting with external providers or remote users.
                      - Open external.xml 
                      sudo nano /usr/local/freeswitch/conf/sip_profiles/external.xml
                        - Update the external IP and port values if needed:
                        xml <param name="sip-ip" value="public.ip.address"/> <param name="rtp-ip" value="public.ip.address"/>

                        Save and close each file, then restart FreeSWITCH to enable these settings.

                        Step 4: Setting Up Dialplans

                        Dialplans control how calls are routed and handled within FreeSWITCH. The default dialplan files are in /usr/local/freeswitch/conf/dialplan.

                          - ***Understanding Contexts*** : Dialplans in FreeSWITCH operate within “contexts,” which are separate groups of rules that define call behavior. The default context is usually set to default.
                          • Editing Default Dialplan :
                            - Open the default.xml dialplan: 
                            sudo nano /usr/local/freeswitch/conf/dialplan/default.xml
                              - Add custom extensions, routing rules, and call-handling logic as needed:
                              xml <extension name="example_extension"> <condition field="destination_number" expression="^1001$"> <action application="answer"/> <action application="playback" data="ivr/ivr-welcome_to_freeswitch.wav"/> <action application="hangup"/> </condition> </extension>
                                - ***Testing Dialplans*** : After editing, reload the dialplan without restarting FreeSWITCH: 
                                   fs_cli -x "reloadxml"

                                Step 5: Codec Configuration

                                Codec selection impacts call quality and bandwidth. FreeSWITCH supports a range of audio codecs, including G.711, G.729, and Opus.

                                  - ***Configure Codecs in SIP Profiles*** :
                                    - Edit internal.xml and external.xml profiles to set preferred codecs:
                                    xml <param name="codec-prefs" value="OPUS,PCMU,PCMA"/>
                                      - ***Enable Transcoding*** : For calls between devices with different codec support, enable transcoding in FreeSWITCH.
                                      • Testing Codec Functionality : Use fs_cli to verify codec setup by running:
                                         sofia status profile internal

                                      Step 6: Configuring NAT Settings

                                      Network Address Translation (NAT) can cause connectivity issues, especially in environments with remote clients or devices behind firewalls.

                                        - ***Configure SIP Profiles for NAT*** : Open the internal and external SIP profiles and add the following NAT settings: 
                                           <param name="ext-sip-ip" value="external.ip.address"/>
   <param name="ext-rtp-ip" value="external.ip.address"/>
   <param name="rtp-timeout-sec" value="300"/>
                                          - ***Set IPs in vars.xml*** : Also set external IPs in vars.xml to ensure correct media routing: 
                                             <X-PRE-PROCESS cmd="set" data="external_rtp_ip=your.external.ip"/>
   <X-PRE-PROCESS cmd="set" data="external_sip_ip=your.external.ip"/>

                                          Step 7: Implementing Security Measures

                                          FreeSWITCH is highly customizable for security, and securing SIP and RTP traffic is essential.

                                            - ***Password Protect SIP Accounts*** : Set strong passwords for each SIP user account in /usr/local/freeswitch/conf/directory/default/.
                                            • IP-Based Restrictions : Limit SIP connections to trusted IP addresses. For example, in internal.xml:
                                               <param name="auth-calls" value="true"/>
   <param name="apply-inbound-acl" value="trusted"/>
                                              - ***Enable TLS for SIP*** : Encrypt SIP communications by enabling TLS in the internal.xml and external.xml profiles: 
                                                 <param name="tls" value="true"/>
   <param name="tls-bind-params" value="transport=tls"/>

                                              Step 8: Testing FreeSWITCH Setup

                                              With configurations complete, test the setup to ensure everything works as expected:

                                                - ***Check SIP Status*** : Use fs_cli to view active SIP profiles and registrations: 
                                                   sofia status
                                                  - ***Test Calls Between Extensions*** : Try making calls between extensions configured in the dialplan to ensure call routing works.
                                                  • Review Logs for Errors : Logs are stored in /usr/local/freeswitch/log/. For example:
                                                     tail -f /usr/local/freeswitch/log/freeswitch.log

                                                  Step 9: Automating Startup and Shutdown

                                                  To automate FreeSWITCH to start on boot, confirm it’s enabled in systemd:

                                                  sudo systemctl enable freeswitch

                                                  To manage FreeSWITCH manually, use:

                                                  sudo systemctl start freeswitch
sudo systemctl stop freeswitch

                                                  Conclusion

                                                  Setting up and configuring FreeSWITCH on Alma Linux offers a comprehensive telephony platform suitable for a range of VoIP and unified communication needs. By following these initial configuration steps, including setting up SIP profiles, dialing plans, codecs, and security options, you’ll be able to make the most of FreeSWITCH’s powerful capabilities. This guide provides a foundation for configuring FreeSWITCH to ensure efficient and secure communication across your network.

                                                  FAQs

                                                  1. Can I use FreeSWITCH for video calls on Alma Linux?
                                                  Yes, FreeSWITCH supports video conferencing and SIP-based video calls. Additional modules and codecs, like VP8, may need configuration.

                                                  2. How can I back up my FreeSWITCH configuration?
                                                  Simply back up the /usr/local/freeswitch/conf directory to save all configuration settings.

                                                  3. What is the default FreeSWITCH admin password?
                                                  FreeSWITCH does not have a default password. Users set this up during initial configuration.

                                                  4. How do I troubleshoot SIP connectivity issues?
                                                  Use the sofia status and sofia status profile <profile_name> commands in `fs

                                                  _cli` to check SIP profiles and diagnose connectivity issues.

                                                  5. Can I run FreeSWITCH with other PBX software?
                                                  While it’s technically possible, it’s recommended to run FreeSWITCH on a dedicated server to avoid conflicts.

                                                  6. What are the best practices for securing FreeSWITCH?
                                                  Implement strong password policies, limit IP access, enable TLS, and configure access control lists (ACLs) for SIP profiles.

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