I was really frustrated that our voicemail was not working in Chrome. All it said was Missing Plug-in.
Through some research, I found that the voicemail system was loading the files via ajax to a PHP script. Because the extension was not .wav, Chrome was confused.
How did I solve?
Well, this is an internal box with very little traffic and I have complete control of it.
I first told Apache to treat all .php.wav files as PHP. In httpd.conf of php.conf you will see
AddHandler php5-script .php
Add this right below it.
AddHandler php5-script .php.wav
Then I symlinked the .php file to a .php.wav file. So that they were identical. Then in the file that pulled in this php file, I changed the filename there as well.
Fixed my issue. 🙂