How safe is Trixbox/A@H on the Internet

[Michael Wong]

Hi folks, can any of the seasoned veterans out there tell me how safe it is
to deploy Trixbox on the internet?  Is installing a FW a good idea?  What
about Fail2ban?  Is it a good idea to install the full gamet of Trixbox?  or
should I only install the components I need?  I want to run a Calling Card
operation on my box and don't know if all the extra components of Trixbox
would slow my box down or even make it vulnerable to an attack!