External SIP or in other words SIP through firewalls and routers or more accurately SIP traversal through Network Address Translation (NAT) is arguably one of if not the most common problem people face.  SIP is notorious for this.  This little article is my attempt to provide a simple no nonsense method of finding and fixing these problems.  Ideally before they ever happen.  To keep it simple I will assume everything on the PBX itself is configured correctly. 

Includes every detail in the form of step by step instructions from bare metal to a running VoIP PBX in about 2 hours.  Because it does not require MySql or Apache, Asterisk GUI v2.x is a good alternative to FreePBX for someone looking for a less resource intensive install, possibly on a flash drive and/or embedded appliance hardware with limited CPU/RAM.  The whole install including source files takes up about 1.2Gigs of drive space and uses about 100MB of RAM while idle.  It could probably be reduced to 1Gig of drive space or less with very little effort.  Assuming you

Here are a few advanced topics covering some things that can be done to any FreePBX or strictly Asterisk distribution.  These would be things one might be interested in doing beyond the standard Linux-Asterisk-Freepbx installation.

In previous posts I showed how to auto-provision and configure Aastra phones by manually installing XML scripts.  Aastra has released RPM packages for Trixbox that combines everything and adds new features as well as mDNS so the phones can find the TFTP server even if you don't have a DHCP server capable of assigning it.  The script won't

Just got back from the Open Telephony Training seminar in Las Vegas.

This is a general overview of some of the more common mile high mistakes people make when doing an open source VoIP PBX project.  I won't be going into details about hardware dimensioning or software configuration.  I will just be providing a general overview of some of the system level common sense mistakes people make in terms of a typical consultant/client type of project.

There is an interesting new VoIP PBX product that has caught my attention.  I even felt compelled enough to get off my lazy butt and write a little review about it.  What caught my attention was that it's from one of my favorite hardware manufacturers.  I make no secret of my love for Aastra SIP phones so when I heard about the AastraLink Pro 160 PBX I had to find out more.  It's not actually shipping till late May 2008 and I’m not enough of a big shot to get any special love from Aastra so I haven't held one in my hands much less take

The following is an update to a case study of a VoIP PBX phone system I installed back in October 2006 using this guide.  I feel it is time for an update to see how things have worked out long term.