Is there a list of files that FreePBX modifies/writes over such as extensions.conf, and files that are safe to modify and add things like dial plans to? There seems to be a lot of confusion as to which .conf files you can or cannot modify. The problem is made worse by most of the documentation present for Asterisk tells you to modify the .conf files directly using a text editor. Bring FreePBX into the picture and your .conf may get written over - losing your configuration.
The rules are pretty straight forward, just not stated in plain site.
You only edit files that end in *_custom.conf. Asterisk assumes that you the user are configuring everything. FreePBX stops you from having to do that by using macros and auto-generated code based on setting, selections and definations you make on your system. Since FreePBX does that it takes over those files and uses includes to call other files that you can edit and override. So the best thing is to read through the files and find what it includes and does not.
There are exceptions to the list. Sip_nat.conf, extenstions_override_freepbx.conf, zaptel.conf are the common ones. I think there are two or three others that I can’t remember off the top of my head.
I’ve put up a webpage that starts to detail the configuration files required for Asterisk and the ones that FreePBX tampers with. It’s located on my PBX in a Flash for Newbies website at:
http://www.cadvision.com/blanchas/Asterisk/ConfigurationFiles.html