If your host name does not resolve correctly you can get an annoying Name or Service not known error when you ask for your fully qualified domain name - even if you have correctly set your full host name. Here's why and what to do about it.
One of lifes great time-savers is Arno's IPTables Firewall
Script. It usually works perfectly with only the most basic configuration - but it takes a bit of thinking to get OpenVPN to run smoothly. This FAQ contains the little details that most people would otherwise have to dig for.