What IS 3CX?

What is 3CX?

It is a software based PBX (Private Branch Exchanged) that is based on SIP (Session Initiation Protocol) standard.

It enables extensions to make calls via PSTN (Public Switched Telephone Network) or via VoIP (Voice over Internet Phone) services. The 3CX for Windows and Linux is an IP business phone system that supports standard SIP soft/hard phones, VoIP services and traditional PSTN phone lines.

This PBX can be accessed and managed via a web-based management console, softphones for Windows and MacOS, and smartphone clients for iOS and Android. The system can be used with either SIP phones, the clients or combination of both. It also provides functions such as chat, voicemail to email, fax to email, integrated video conferencing, call conferencing, and CRM intergration.

Configuring VoIP Providers or SIP Trunks – 3CX

VoIP Providers or SIP Trunks delivers telephone services and unified communications to customers who uses and are equipped with SIP Based PBX like 3CX.
Unified communications applications provides services like; voice calls, video conferencing, and web conferencing.


  • Supported VoIP provider (SIP Trunk)
  • Firewall tested and passed
  • Supported VoIP Provider
    • Easy Setup
    • Tested and passed by 3CX
    • Supported by 3CX Support
  • Generic VoIP Provider
    • Not tested by 3CX
    • No available 3CX Support
  • Provides Public Switched Telephone Numbers (PSTN)
  • Transmit via existing Internet Connection

Adding a Provider:

Configuring the Firewall – 3CX

Firewall configuration is a requirement for 3CX to work properly on the system. There are settings that needs to be changed for Voice Calls and other features to work and connect to the 3CX server.


  • Basic Knowledge in Routing
  • Configurable Firewall
    • pfSense
    • WatchGuard
    • Sonicwall
  • Knowledge on the Firewall device

Note: 3CX Support will NOT configure your firewall for you.

Informations on NAT (Network Address Translation) and Ports:

  • It translates Public Address (IPv4) to Private IP Addresses (NAT/PAT)
  • It allows or restricts. ACL (Access Control List)

Configuring a Desktop Telephone – 3CX

A 3CX Supported IP Phones

  • Fanvil
  • Grandstream
  • Htek
  • Snom
  • Yealink

See the full list of supported IP phones and firmwares informations at www.3cx.com/support

IP Phone Provisioning

Is the process of setting up a predefined configuration to an IP phone. This removes human error from manually doing a configuration and speeds up the deployment.

PnP Provisioning (User Extensions)

  • Boot Up to the Desktop Phone
  • From the Management Console, go to Phones Node
  • Select the “Bold” entry then Add New Extension or Add to an existing extension

3CX Client Installation

3CX Client is a software application that can run on supported devices (PC, Mac or Mobile Devices).
It provides telephone functions for internal or external use and can run alongside with IP phones using the same extension number.


  • Operating Systems – Desktops
    • Windows PC
      • Windows 7 SP1 or higher versions (Preferred Windows 10)
    • Apple
      • Mac OS 10 or higher versions (Preferred Mac OS 10.13 – High Sierra)
  • Operating Systems – Mobile Devices
    • Apple iOS (includes iPhone, iPad and iPod)
      • iOS 10 or higher versions
      • An App Store account

Configuring the 3CX Client

Provisioning is a method of providing configuration using prefilled settings that the vendor uses.
It speeds up the deployment and prevents human errors on the installation process.
This is a technique which 3CX prefers to use.

2 types of 3CX provisioning:

  • Welcome Email Provisioning
    • Universal for all 3CX Clients
    • Admin triggered or automatically sent upon extension creation
    • All instructions provided within the email
    • Configuration attachment and automatically installed once executed
  • QR Code Provisioning (Mobile Device Clients)
    • No email access required
    • No email attachments for automatic configuration installation
    • Access via web client

3CX Installation

Installing 3CX

System Requirements:

Supported Operating Systems

  • Linux Debian 9
    • Dedicated server for 3CX
    • There should be NO 3rd Party softwares like DNS and VPN
  • Microsoft Windows 10 64 Bit (Pro or Enterprise)
  • Microsoft Server 2016, 2012 or 2012 R2 (Preferred is 2016)
    • with complete Windows Update and .Net 4.6.1 required
    • Compatible browsers are Chrome, Edge and Firefox
    • No 3rd Party softwares installed
    • Needs to be excluded from the Antivirus for the 3CX folders and network traffic
  • Running as Local Virtual Machine (3CX Tested Hypervisor Platforms)
    • Microsoft HyperV (Higher than 2008 R2)