td {border:solid 1px #777777; padding:0.5ex;}

Purchasing a router may sound like a pretty simple task. This however can become somewhat challenging when VOIP comes into play.
There a couple of core functions that your choice of router …

Many users are battling with Sonicwall devices, and even though 3CX cannot provide support for this, we have the following notes to hopefully help you with your configuration.

Correct Router Configuration is a key element in ensuring correct communications between 3CX PhoneSystem and external entities such as external extensions, VoIP Provider services, and other Bridged PBXs.
NAT and/or PAT
When a network host A sends …

If you have been asking yourself how to secure 3CX PhoneSystem, read on…

In this article we will describe the configuration of a hardware router with a very attractive quality-price ratio. The Draytek 2820 is a ADSL 2/2+ Router/Firewall with advanced features such as the capability to establish …

This document will provide an overview of the more common concepts which need to be kept in mind when configuring 3CX PhoneSystem inside your network infrastructure, including the following topics:

NAT Configuration
STUN Resolution
DNS Resolution in a …

In order for 3CX Phone System to communicate successfully with VoIP providers and Remote Extensions, your firewall/router device must be configured for SIP operation. To maximize your chances of success, make sure you choose a …

The following is a complete list of ports that 3CX PhoneSystem uses in a default installation scenario:

TCP:80
…
If 3CX is installed for IIS, this is the default port number to reach the 3CX Management Console (http://<ip_of_pbx>/management) …

Introduction
The 3CX Firewall Checker checks whether the ports needed to communicate with your VOIP provider are open and properly configured with STATIC Port mapping. If the firewall checker does not complete successfully, you will not …

Click to download the stand-alone SIP Proxy Manager
What is the 3CX SIP Proxy manager
The SIP Proxy Tunnel can combine all SIP (signaling) and RTP (media) VoIP Packets from one location (typically a remote office) …

Introduction
3CX Phone System frequently communicates across LANs and establishes calls between devices (softphones, hardphones, gateways, VoIP providers, and PBX bridges) which are located on different networks. The PBX communicates both with devices that are inside …

The issues with Microsoft ISA server 2004 and 2006
Unlike most professional firewalls, Microsoft ISA server is not able to do static port mapping. Without static port mapping it is not possible to reliably connect to …

If you are using a VOIP provider, then you will have to configure your firewall correctly in order to get reliable results. Your firewall must support STATIC PORT MAPPING.
3CX Phone System needs the following ports …

So you have installed 3CX PhoneSystem, your VoIP Provider account registers fine, a couple of test calls successfully prove that all is working. It’s now time to put things into production.
And as soon as you …

If you are using a VOIP provider, you will need to have a firewall that supports and is configured to use static port mapping. Static port mapping is required for RTP, the protocol that carries …

If you are using a VOIP provider, then you will have to configure your firewall correctly in order to get reliable results. Your firewall must support STATIC PORT MAPPING.
3CX Phone System needs the following ports …

In the VoIP / telecommunications  field, the term QoS (Quality of Service) refers to resource reservation control mechanisms. Quality of service is the ability to provide different priority to different applications, users, or data flows, …

How and when can I switch off STUN Resolution
STUN resolution is necessary for the PBX to understand what it’s public IP Address is, and what port mappings are in effect for Media (to attempt NAT …